Cenomanian Angiosperm Leaf Megafossils, 

Dakota Formation, 

Rose Creek Locality, Jefferson County, 

Southeastern Nebraska 
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Cenomanian Angiosperm Leaf Megafossils, 

Dakota Formation, 

Rose Creek Locality, Jefferson County, 

Southeastern Nebraska 

By GARLAND R. UPCHURCH, JR. and DAVID L. DILCHER 

U.S. GEOLOGICAL SURVEY BULLETIN 1915 
DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, or firm names in this publication is for descriptive 

purposes only and does not imply endorsement by the U.S. Government. 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1990 

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Library of Congress Cataloging-in-Publication Data 

Upchurch, Garland A. 

Cenomanian angiosperm leaf megafossils, Dakota Formation, Rose Creek 

locality, Jefferson County, southeastern Nebraska I by Garland A. Upchurch, 

Jr., and David L. Dilcher. 

p. cm.-(U.S. Geological Survey bulletin; 1915) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.3:1915. 

1. Leaves, Fossil-Nebraska-Jefferson County. 

2. Paleobotany-Cretaceous. 3. Paleobotany-Nebraska-Jefferson 

County. I. Dilcher, David L. II. Title. Ill. Series. 

QE75.89 no. 1915 

[QE983] 

557.3 s-dc20 90-2855 

[561 '.2]CIP 
CONTENTS 

Abstract 1 

Introduction 1 

Acknowledgments 2 

Materials and methods 2 

Criteria for classification 3 

Geological setting and description of fossil plant locality 4 

Floristic composition 7 

Evolutionary considerations 8 

Ecological considerations 9 

Key to leaf types at Rose Creek 10 

Systematics 12 

Magnoliales 12 

Laurales 13 

cf. Illiciales 30 

Magnoliidae order unknown and magnoliid-grade foliage 34 

Rosidae 42 

Magnoliopsida subclass unknown 45 

References cited 49 

Index 53 

PLATES 

[Plates follow index] 

1. New genus A 

2. Extant Magnoliales 

3. Crassidenticulum decu1Tens 

4. Crassidenticulum decu1Tens 

5. DensineJVum kaulii 

6. Gomorlega keule and Landonia calophylla 

7. Extant Laurales 

8. Pabiania variloba 

9. Pabiania variloba and extant Laurales 

10. Extant Laurales 

11. Cuticle of Pabiania variloba and Sassafras albidum 

12. Pandemophyllum kvacekii 

13. Pandemophyllum kvacekii and Pandemophyllum attenuatum 

14. Fossil leaves similar to Pandemophyllum and Pandemophyllum sp. 

15. Cuticle of Pandemophyllum kvacekii 

16. Cuticle of Pandemophyllum attenuatum and Pandemophyllum sp. 

17. Cuticle of Pandemophyllum sp. and extant Lauraceae and Staudtia gabonesis 

18. Longstrethia varidentata 

19. Cuticle of Longstrethia varidentata 

20. Cuticle of Longstrethia varidentata; extant Illiciales 

21. Didromophyllum basingerii 

22. Didromophyllum basingerii and "Sterculia" towneri var. disjuncta 

23. Acritodromum ellipticum and Reynoldsiophyllum masonii 

Contents Ill 
PLATES 

24. Reynoldsiophyllum nebrascense 

25. "Elaeodendron" speciosum, Dicotylophyllum angularis, and New genus B 

26. Anisodromum wolfei 

27. Citrophyllum doylei and Citrophyllum aligentm 

28. Dicotylophyllum myrtophylloides 

29. Dicotylophyllum rosafluviatilis 

30. Dicotylophyllum aliquantuliserratum 

31. Dicotylophyllum expansolobum 

FIGURES 

1. Index map showing location of the Rose Creek locality, Jefferson County, 

Nebraska 5 

2-25. Line drawings showing: 

2. New genus A 12 

3. Crassidenticulum decurrens 14 

4. Ascarina lanceolata 15 

5. DensineTVUm kaulii 18 

6. Gomortega keule 19 

7. Landonia calophylla 19 

8. Pabiania variloba 22 

9. Pabiania variloba 23 

10. Pandemophyllum kvacekii 26 

11. Pandemophyllum attenuatum 29 

12. Longstrethia varidentata 31 

13. Schisandra propinqua 33 

14. Didromophyllum basingerii 34 

15. Acritodromum ellipticum 36 

16. Reynoldsiophyllum masonii 38 

17. Reynoldsiophyllum nebrascense 39 

18. Dicotylophyllum angularis 40 

19. New genus B 41 

20. Anisodromum wolfei 42 

21. Citrophyllum doylei 43 

22. Dicotylophyllum myrtophylloides 45 

23. Dicotylophyllum rosafluviatilis 46 

24. Dicotylophyllum aliquantuliserratum 41 

25. Dicotylophyllum expansolobum 49 

TABLES 

1. Comparison of Crassidenticulum, DensineTVUm, and related extant taxa 16 

2. Comparison of Landonia and related extant taxa 21 

3. Comparison of Pabiania, Pandemophyllum, and related taxa 25 

IV Contents 
Cenomanian Angiosperm Leaf Megafossils, 

Dakota Formation, Rose Creek Locality, 

Jefferson County, Southeastern Nebraska 

By Garland R. Upchurch, Jr. and David L. Dilcher1 

• 2 

ABSTRACT 

The leaves described in this report comprise the first 

assemblage of early flowering plant leaf megafossils to be 

accorded formal systematic treatment using modern 

methods of foliar architecture and cuticular anatomy. The 20 

species of dicotyledonous leaves are described from a new 

locality in the Dakota Formation of Nebraska, near Rose 

Creek (Rose Creek locality). Seventy percent of the species 

represent either subclass Magnoliidae or forms with a similar 

grade of foliar architecture. Among Magnoliidae, species are 

assignable to the orders Magnoliales and Laurales, and one 

species shows resemblance to llliciales. Although three 

species have strong similarities to one extant family (Lauraceae, or the laurel family), most species of Magnoliidae or 

magnoliid-grade foliage possess generalized features or 

combine the characteristics of two or more extant families. 

One species possesses unique features of foliar architecture 

that represent an unsuccessful •experimental• design. Two 

species of Rosidae are present in the flora, and these 

combine features of foliar architecture that today are 

restricted to either compound-leaved or simple-leaved 

families. The leaves examined in this study show little 

evidence for fragmentation prior to burial and are preserved 

in a sequence of rooted mudstones containing brackishwater bivalves (including one specimen in life position); thus, 

the leaves represent predominantly local, brackish-water 

vegetation. This indicates that flowering plants evolved the 

ability to tolerate greater-than-freshwater salinities by the 

Cenomanian. The vegetation represented by the Rose Creek 

leaf remains shows few similarities to modern mangrove 

swamps but instead is most analogous to brackish-water 

swamps that occur inland from mangrove swamps. 

Manuscript approved for publication, October 20, 1989. 1

Department of Biology, Indiana University, Bloomington, 

Indiana, 47405. 

2 Address as of June 1990: Florida Museum of Natural History, 

University of Florida, Gainesville, Florida, 32611. 

INTRODUCTION 

The mid-Cretaceous was an important period in 

the history of the vascular land plants. During this time, 

the angiosperms began their adaptive radiation, and 

major extant lineages at the level of subclass, order, and 

family made their first appearance. (See, for example, 

Wolfe and others, 1975; Hickey and Doyle, 1977; 

Dilcher, 1979; Upchurch, 1984; Walker and Walker, 

1984.) Associated with this adaptive radiation were 

progressive and broad-scale ecological displacements, 

wherein cycadophytes, ginkgophytes, and other dominant 

groups of gymnosperms declined in relative abundance 

and diversity and were replaced in most habitats and 

geographic regions by angiosperms, especially at lower 

and middle paleolatitudes (Doyle and Hickey, 1976; 

Hickey and Doyle, 1977; Retallack and Dilcher, 1981, 

1985; Crane, 1987; Upchurch and Wolfe, 1987b). 

Although some aspects of this transition have been 

elucidated by recent paleobotanical research, much 

remains unknown about this critical interval of Earth 

history, particularly with respect to the dynamics of 

angiosperm diversification and the establishment of 

major extinct and extant angiosperm lineages. 

This state of ignorance is largely due to an inadequate taxonomic data base, a problem that is especially 

acute for angiosperm leaf megafossils. During the 19th 

and early 20th centuries, paleobotanists described 

numerous angiosperm leaf remains of Cretaceous age, 

but without a clear understanding of foliar architecture 

and the systematic distribution of foliar architectural 

features in extant flowering plants (Wolfe, 1973; Dilcher, 

1974; Doyle and Hickey, 1976). Compounding the problem was an automatic assignment of most fossil leaves to 

extant families and genera, even if these leaves lacked 

one or more features found in the extant taxa. This 

"picture matching" (Wolfe 1973; Dilcher, 1974) gave the 

Cretaceous angiosperm record a falsely modern aspect, 

Introduction 
preventing the recognition of extinct evolutionary 

intermediates and disguising similarities that were the 

result of convergent evolution. As a result, even the 

oldest known angiosperm leaf assemblages were inferred 

to show affinities with both primitive and derived taxa, 

and few angiosperms were thought to represent extinct 

intermediate forms. While some authors explained this 

situation by proposing extremely rapid evolution of 

flowering plants during the Cretaceous (Scott and others, 

1960), others proposed an extensive period of diversification prior to the group's appearance in the fossil 

record, either in remote geographic regions (Seward, 

1931) or in upland regions, where preservation of preTertiary sediments is minimal (Axelrod, 1952, 1970). 

These concepts were consistent with occasional reports 

of pre-Cretaceous flowering plants (for example, Harris, 

1932; Erdtman, 1948; Kuhn, 1955; Brown, 1956; Tidwell 

and others, 1970), now either discounted or considered 

problematic on morphological or stratigraphic grounds 

(Read and Hickey, 1972; Scott and others, 1972; Wolfe 

and others, 1975; Hickey and Doyle, 1977). 

The purpose of this study is to partially redress the 

systematic problem for early angiosperm foliage through 

analysis of leaf architecture and cuticular anatomy in 

well-preserved leaf remains from the mid-Cretaceous 

(uppermost Albian? to middle Cenomanian) Dakota 

Formation of southeastern Nebraska, along with a few 

related forms from the classic Dakota assemablages of 

Kansas. In this report we propose new species and genera 

that more accurately reflect the interrelationships of 

mid-Cretaceous angiosperms. We also discuss probable 

extant affinities at the level of family, order, and subclass, 

based on detailed consideration of foliar architecture and 

cuticular anatomy. These data will serve as a basis for 

elucidating the evolutionary status of early angiosperms 

during the early Cenomanian, approximately 20 million 

years into the angiosperm adaptive radiation. 

ACKNOWLEDGMENTS 

We thank Jack A. Wolfe (U.S. Geological Survey, 

Denver) for his discussions concerning the systematic 

affinities of the Rose Creek foliage, for discussions of the 

issues raised in this report, and for critical review of the 

manuscript. We thank James Basinger (University of 

Saskatchewan, Saskatoon) for his initial research on the 

Rose Creek leaf flora and for preparing most of the 

cuticles examined during this study. We also thank Roger 

Pabian (Nebraska Geological Survey) for discovery of 

the Rose Creek locality, help with geological problems, 

and field assistance, and Howard Reynolds (Fort Hays 

State University, Kansas) for initially informing us about 

the Rose Creek locality and for field reconnaissance. We 

thank Bruce H. Tiffney for careful and helpful review of 

the manuscript. Mr. and Mrs. Richard DeBoer granted 

permission to collect at the Rose Creek locality, and 

Roger Judd of the Endicott Clay Products Company 

provided the services of a bulldozer. Field assistance was 

provided by James Basinger, Charles Beeker, Margaret 

Bolick, Peter Crane, Peter Dilcher, Martin Farley, Karl 

Longstreth, Greg Retallack, and Michael Zavada. 

Insightful comments on the relationships of the Rose 

Creek leaf fossils were provided by Leo Hickey and 

Scott Wing. William Cobban and Douglas Nichols (U.S. 

Geological Survey, Denver) provided assistance with 

stratigraphic problems. The research for this report was 

completed while the senior author was a National 

Research Council Postdoctoral Research Associate at 

the U.S. Geological Survey, Denver. Fieldwork and the 

earlier stages of research were supported by National 

Science Foundation Grants DEB-79-10720 and 

BSR-83-00476 to David L. Dilcher at Indiana 

University, Bloomington. The final stages of data analysis 

and writing were supported by National Science 

Foundation Grant BSR-86--07298 to Garland R. 

Upchurch, Jr. and Erie G. Kauffman at the University of 

Colorado, Boulder, and by National Science Foundation 

Grant BSR-85-16657 and a Guggenheim Foundation 

Fellowship to David L. Dilcher at Indiana University, 

Bloomington. 

MATERIALS AND METHODS 

Nearly every specimen examined during this study 

was collected between June 1978 and October 1983. All 

distinctive leaf architectural types and all specimens with 

organic preservation were retained for laboratory 

analysis, and many of the organically preserved specimens were coated with Krylon crystal clear acrylic plastic 

spray to prevent cracking of the organic matter. All 

collected specimens were initially deposited in the 

Indiana University paleobotanical collections and given 

the locality prefix 15713-. These collections are now 

housed at the Florida Museum of Natural History in 

Gainesville, Florida. 

Foliar architecture of fossils was studied through 

direct observation of specimens and through enhancement of details by line drawings and high-contrast 

photography with Kodak Technical Pan 2415 film. Leaf 

architectural terminology largely follows Hickey (1973, 

1979) but incorporates the modifications suggested by 

Wolfe (1977) and Wolfe and Wehr (1987) with three 

exceptions. First, we have used Hickey's term "exmedial" 

instead of "abmedial," largely because abmedial is easy 

to confuse with admedial. Second, we have used 

"quaternary" and "quinternary" instead of "quatary" and 

"quintary." Third, we have avoided use of Hickey's terms 

"imperfect," "incomplete," and "lacking" for the 

2 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
description of areolation. These three conditions intergrade and represent a composite of characters (variation 

in areolar size, shape, and degree of branching of the 

freely ending veinlets ), and we could not be confident 

that we were always using the terms in the manner 

intended by Hickey (1973, 1979). Instead, we have 

described areolation as well developed, moderately 

developed, or poorly developed, depending on the 

regularity in size and shape, and provided illustrations for 

the reader. We also have added descriptions of the 

general organizational tendencies in festooned brochidodromous secondary venation. Readers unfamiliar with 

venational terminology should obtain a copy of Hickey 

(1979) to use while reading species descriptions. 

Cuticles were prepared for light microscopy with a 

combination of standard methods, such as those outlined 

in Dilcher (1974), using bleach for maceration and 

Safranin 0 for staining. When cuticular fragments were 

large, a piece of 100-mesh screen was sometimes used to 

transfer cuticle between solutions. All leaf cuticles were 

photographed with Kodak Technical Pan 2415 film on 

the Zeiss Photoscope I at the Paleontology and Stratigraphy Branch, U.S. Geological Survey, Denver, using 

brightfield and phase-contrast optics. Cuticular terminology follows Stace (1965) and Dilcher (1974), except 

when the use of terminology would potentially confuse 

the nonspecialist. "Upper" cuticle is used in place of 

"adaxial" cuticle and "lower" cuticle is used in place of 

"abaxial" cuticle. This is because the upper and lower 

cuticle in fossils are recognized by an ecologically 

controlled character (frequency of stomata), while abaxial and adaxial denote developmental position. (In the 

mature leaves of a few extant species, the lower surface 

actually represents the adaxial side of the developing 

leaf.) The term "cuticular flange" is used in place of 

"anticlinal cell wall" because the cuticular flanges are the 

only part of the anticlinal walls preserved in most 

cuticular preparations. All measurements of cell size are 

for unspecialized cells. Cells from modified areas of the 

epidermis in proximity to veins ("veinal areas") and 

stomata were not included in the measurements. · 

Because foliar architecture and cuticular anatomy 

in extant flowering plants have not been comprehensively 

described and illustrated, we have included illustrations 

of extant relatives of the Rose Creek taxa. Complete 

illustration of foliar architecture and cuticular anatomy 

in the extant relatives would be a major undertaking and 

was not attempted because of limited time and space; 

instead, we illustrated only representative taxa. Most 

photographic illustrations of foliar architecture are x 1 

but can be magnified for observation of secondary, 

tertiary, and quaternary venation. Illustrations of tooth 

architecture are largely confined to line-drawings; the 

interested reader should consult Hickey and Wolfe 

(1975) for photographic illustrations of major tooth types 

in extant flowering plants. 

CRITERIA FOR CLASSIFICATION 

Angiosperm phylogeny is riddled with examples of 

convergent morphologies, and individual plant organs 

show a large degree of developmental independence 

relative to one another. Together these create the 

potential for strong mosaic evolution. Any classification 

based on a single organ has a greater potential for error 

than one based on a variety of organs, because whole 

plants contain a larger number of nondevelopmentally 

linked characters than single organs. Hence, the analysis 

of whole plants improves the chances of spotting 

convergent similarities. However, while leaves are the 

most abundant component of the megafossil record, 

foliar characters have traditionally played a small role in 

the classification of extant angiosperms, in contrast to 

reproductive structures. Although one solution to this 

problem would be to restrict the systematic analysis of 

angiosperm megafossils to taxa known from both 

reproductive and vegetative organs, this approach would 

greatly restrict information about the flora as a whole, 

given the dominance of isolated vegetative organs in the 

megafossil record. 

Fortunately, comparative studies of extant angiosperms indicate that leaves show a number of features of 

systematic importance at the levels of genus, family, 

order, and subclass; (Wolfe, 1973; Hickey and Wolfe, 

1975; Roth, 1981; Jones, 1984; Levin, 1986a, b). In 

particular, features, such as venation pattern, tooth 

structure, and leaf organization, show strong correspondence with recent angiosperm classifications based 

on more traditional botanical characters taken from a 

variety of plant organs. (See, for example, Cronquist, 

1968, 1981; Takhtajan, 1969, 1980.) Studies of foliar 

architecture also have resolved the systematic placement 

of taxa whose classification proved problematic on the 

basis of reproductive organs. The most prominent 

example at the level of subclass is Euphorbiaceae, where 

foliar architecture (Hickey and Wolfe, 1975) strongly 

supports Takhtajan's (1969, 1980) placement of the 

family within Dilleniidae, rather than Rosidae, as 

proposed by Cronquist (1968, 1981). At lower taxonomic 

levels, the combination of foliar architecture and epidermal anatomy have resolved the systematic placement 

of various problematic taxa, including several genera 

within the subfamily Phyllanthoideae of the Euphorbiaceae (Levin, 1986a, b). Thus, foliar characters have 

much potential for the classification of fossil angiosperms, especially if venation is combined with 

Criteria for Classification 3 
anatomical features, such as stomatal structure and trichome type, which are routinely analyzed by systematic 

plant anatomists. 

We followed four major principles to minimize 

potential error in our classification of fossil angiosperm 

foliage. 

First, the only characters used to circumscribe 

fossil genera were those that have systematic significance 

in extant angiosperms at the level of genus or family. This 

was determined by direct study of the foliar architecture 

and epidermal anatomy of extant angiosperms and by 

examination of the literature on foliar architecture (for 

example, Hickey and Wolfe, 1975; Levin, 1986a, b) and 

anatomy (for example, Metcalfe and Chalk, 1950, 1979; 

Wilkinson, 1979). For members of the subclass Magnoliidae, this comparison was exhaustive and involved examination of over 260 extant genera. Approximately 4000 

total extant species were examined for foliar architecture. 

Second, new genera were erected only on the basis 

of several independent and congruent characters, so as to 

avoid the pitfalls of single character taxonomy. In order 

to be considered independent, two characters must have 

a different developmental origin or show distinctly 

different constructional principles. For example, both 

foliar venation and cuticular anatomy were used in 

diagnosing genera because the veins and cuticle have 

their developmental origins in different tissue layers of 

the leaf (Fahn, 1967). For another example, the presence 

of two or more vein orders with a particular venational 

pattern (such as reticulate tertiary and quaternary venation) was counted as only a single character, because this 

condition could easily result from the iteration of the 

same developmental pattern at different levels of the 

venational hierarchy. For the sake of completeness, 

potentially linked characters were listed separately in the 

descriptions of species. 

Third, all leaf remains that formed the basis for 

generic diagnoses had to be known with at least three or 

four orders of preserved venation and be represented by 

sufficient specimens to understand the construction of 

the whole leaf. This insured that a large number of 

venational characters was considered before erecting a 

classification and that all diagnostic features were 

present in the type species. This also prevented erroneous assignment of fossil leaves to the most similar 

extant taxon, because many times the similarities seen 

between a fossil leaf and an extant taxon were in lower 

order architectural features and cuticular anatomy, 

rather than in fine venation. 

Fourth, a leaf taxon had to show either probable 

congeneric relationship to other fossil species or a highly 

distinctive suite of features before being formally 

diagnosed at the generic level. If a fossil leaf type met 

only three of these criteria (for example, it was 

represented by an incompletely preserved specimen that 

had a distinctive suite of leaf architectural features 

unknown in any extant family), a generic level taxon was 

informally recognized, permitting diagnosis when better 

preserved specimens are found. If a leaf type was 

distinctive at the species level but had incompletely 

preserved venation or a generalized suite of venational 

features, the leaf was assigned to Dicotylophyllum. 

In this report we make extensive comparisons 

between species in the Rose Creek flora and previously 

reported taxa. The discussion section following most 

species descriptions is divided into three parts. The first 

part compares the taxon with previously described fossil 

genera and discusses the validity of previous generic 

assignments, largely to justify the creation of new genera. 

The second part compares the Rose Creek species with 

previously described species of fossil angiosperm leaves, 

many of which were invalidly assigned to extant or fossil 

genera. This is done to justify creation of new species and 

to point out possible congeneric species from other 

floras. The third part provides the basis for assignments 

to extant taxa, starting at the level of class or subclass and 

working down the level of family. 

Many discussion sections might seem lengthy by 

the standards of Tertiary paleobotany. This lengthiness is 

necessitated by the prior identification of species by some 

workers solely on the basis of shape and size and by 

widespread misidentification of mid-Cretaceous angiosperm foliage at generic and higher taxonomic levels, 

practices that, unfortunately, continue to the present day. 

We hope that these comparisons will suggest avenues for 

future research on the systematics of Cretaceous angiosperm foliage. 

GEOLOGICAL SETTING AND 

DESCRIPTION OF FOSSIL PLANT 

LOCALITY 

In central Kansas and adjacent regions, the midCretaceous sequence comprises five distinct formations, 

considered to represent the early stages of the Greenhorn transgression by Kauffman (1969). In ascending 

stratigraphic order these units are as follows: (1) the 

Cheyenne Sandstone of middle to late Albian age, (2) the 

Kiowa Formation of late Albian age, (3) the Dakota 

Formation of latest Albian (?) to middle Cenomanian 

age, (4) the Graneros Formation of middle Cenomanian 

age, and (5) the Greenhorn Formation of late Cenomanian to Turonian age (Hattin, 1967; Kauffman, 1969; 

Franks, 1975; Ward, 1986). Although the full stratigraphic sequence is exposed in central Kansas, older 

units successively pinch out to the northeast, so that in 

southeastern Nebraska rocks of the Dakota Formation 

4 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
97°1 0' 49" 

40° 

03' 

57" 

To Fairbury 

1 MILE 

1 KILOMETER 

Figure 1. Map showing the location of the Rose Creek leaf megafossil locality (from the Fairbury 

SW 7.5-Minute Quadrangle, Nebraska-Kansas). The exact topography of the clay pit has changed 

somewhat since the publication of this map. 

unconformably overlie rocks of Permian age (Franks, 

1975). In southeastern Nebraska and north-central 

Kansas, the Dakota Formation is divided into two 

members (Plummer and Roemary, 1942): (1) the Terra 

Cotta Clay Member, which comprises largely sandstones 

and gray and red mottled claystones; and (2) the Janssen 

Clay Member, which comprises largely sandstones, gray 

claystones, and lignites. The estimated thickness of the 

Dakota Formation in southeastern Nebraska is 200-

400 ft (Franks, 1975). 

The leaf assemblage described in this report was 

collected from the upper half of the Janssen Clay 

Member in a clay pit located 6 miles south of Fairbury, 

Nebraska and 1.1 miles south of Rose Creek, approximately 50-100m east of Nebraska State Highway 15, on 

the west-facing wall of the pit (W¥2NW¥4SE¥4 T. 1 N., 

R. 2 E., Fairbury SW 7 .5' Quadrangle, NebraskaKansas) (fig. 1). Because of the proximity of the clay pit 

to Rose Creek, the megaflora} locality is known as the 

"Rose Creek Locality." Field observations from near the 

study site indicate that the leaf megafossil beds are no 

more than 20 m stratigraphically below the contact 

between the Dakota and Graneros Formations and could 

be much closer. Unfortunately, the Dakota-Graneros 

contact could not be observed unequivocally at the study 

site due to vegetational cover. 

Evidence from palynology, macroinvertebrates, 

and lithostratigraphic position indicate that the Rose 

Creek leaf remains are probably early to middle 

Cenomanian in age. Farley and Dilcher (1986) reported 

Geological Setting and Description of Fossil Plant Locality 5 
a palynoflora from a lignitic clay exposed a few meters 

above the leaf-bearing horizon at Rose Creek and concluded that this palynoflora and other assemblages from 

the Dakota Formation of Kansas indicate a Cenomanian 

age. Examination of the species list presented by Farley 

and Dilcher (1986) indicates a probable correlation with 

Zone III of the Atlantic Coastal Plain, considered early 

to middle Cenomanian in age by Doyle and Robbins 

(1977); in addition, some pollen species listed for Rose 

Creek have their first occurrences within the Western 

Interior in rocks dated as Cenomanian on the basis of 

marine invertebrates (see below). A Cenomanian age for 

the Rose Creek locality is indicated by the combined 

occurrence of (1) long-ranging spore and pollen taxa, 

such as Appendicisporites, Gleicheniidites, and Classopollis, which occur throughout most of the Cretaceous, 

(2) forms, such as Rugubivesiculites rugosus and Tricolpites sagax, which first appear in Subzone II-B (middle to 

late Albian) of the Atlantic Coastal Plain and in middle 

to upper Albian rocks of the Western Interior (Doyle 

and Robbins, 1977 and references cited therein), and 

(3) angiospermous pollen types such as Tricolporopollenites aliquantulus that are indicator species for Zone III of 

the Atlantic Coastal Plain and first occur within the Gulf 

Coastal Plain sequence in the Cenomanian Red Branch 

Member of the Woodbine Formation (Doyle and Robbins, 1977; Hedlund, 1966). Consistent with a Zone III 

age is the high diversity and high relative abundance of 

simple, pinnately veined angiosperm leaves at Rose 

Creek, because similar assemblages are not known from 

the Atlantic Coastal Plain until Zone III (Upchurch and 

Wolfe, 1987b ). 

Direct dating of Dakota rocks by macroinvertebrate fossils in Kansas and northeastern Nebraska indicate an age no younger than late-middle Cenomanian for 

the Rose Creek leaf locality. Macroinvertebrate assemblages described by Hattin (1967) from north-central 

Kansas indicate a middle Cenomanian age for the upper 

few meters of the Dakota Formation, and assemblages 

described by Cobban and Merewether (1983) from 

northeastern Nebraska place the Dakota-Graneros contact at the middle-upper Cenomanian boundary. An age 

no younger than early-middle Cenomanian is implied by 

the absence of Normapolles in palynofloras from Rose 

Creek and other Dakota localities (Farley and Dilcher, 

1986), because Normapolles are first known from uppermiddle Cenomanian rocks of Europe (Doyle and Robbins, 1977). 

Sedimentological and paleontological data indicate 

that the Dakota Formation of central Kansas and southeastern Nebraska was deposited on a low-lying coastal 

plain under predominantly fluvial conditions, with estuarine conditions possibly present in the upper few meters 

of the formation (Hattin, 1967; Franks, 1975; Karl, 1976; 

Siemers, 1976). Deltaic environments may also have 

been widespread but not preserved due to extensive 

reworking of sediments by the transgressing Graneros 

sea (Franks, 1975). Karl (1976) provided evidence for 

predominantly fluvial conditions in the Dakota Formation of southeastern Nebraska, with major 

stratigraphic trends in stream sinuosity, grain size, and 

cross stratification related to a change in stream 

gradients from the transgressing Graneros sea. Karl 

(1976) suggested that the Janssen Clay Member was 

deposited by high-sinuousity meandering streams that 

were preserved as fine-grained, trough- and epsiloncross-stratified, lens-shaped sandstone bodies. Higherthan-freshwater salinities for some parts of the Janssen 

Clay Member are indicated by (1) the occurrence Brachidontes bivalves in association with the leaf remains at 

Rose Creek, including one specimen in life position 

(Retallack and Dilcher, 1981), and (2) the occurrence of 

more fully marine molluscan assemblages and dinoflagellates 13 miles downdip to the northwest, a few meters 

below the contact with the Graneros Formation (Veatch, 

1969). These assemblages are consistent with Hattin's 

(1967) postulation of extensive coastal swamps in the 

Dakota Formation of southeastern Nebraska. Farley and 

Dilcher (1986) proposed the possibility of deltaic 

conditions for the Janssen Clay Member in the Rose 

Creek area, based on (1) evidence for rapid sediment 

deposition, and (2) the occurrence of polymodal crossbedding in a channel 2 m stratigraphically below and 

2 km to the south of the Rose Creek pit. 

The leaf remains at Rose Creek are confined to 

lowermost unit described by Farley and Dilcher (1986), 

which occurs several meters below the pollen-bearing 

horizon. Nearly all identifiable leaf remains occur within 

a 2-m-thick interval of light gray, jointed, overbank 

mudstones. A few identifiable leaf megafossils occur in 

an underlying dark gray mudstone that contains pyritic 

nodules and dispersed pyrite, but these were not 

analyzed because of poor preservation. The floral 

remains described by Basinger and Dilcher (1984) occur 

within a 0.3-m-thick zone in the middle part of the 

leaf-bearing horizon. Most leaf species show little 

evidence for fragmentation prior to burial; the bulk of 

fragmentation exhibited by the specimens results from 

extensive jointing of the mudstone after deposition of 

fossil leaves. Leaves sometimes occur in 1- to 2-cm-thick 

layers separated by much thicker layers of barren 

sediment. Roots occur in association with the leaves and 

are typically preserved as impressions. Rooted layers 

typically occur no more than 20 em above a concentration 

of fossil leaves. Branch roots can penetrate right through 

a leaf vertically, producing little distortion (pl. 24, fig. 5). 

The low distortion of fossil leaves by penetrating roots 

indicates that sediment deposition was rapid, because 

low rates of sediment deposition would be characterized 

6 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
by extensive root bioturbation and high distortion and 

fragmentation of leaf remains. Penetration of the leaf 

bed by roots long after deposition seems unlikely, 

because the roots are concentrated in numerous layers 

(rather than one layer near the top of the sequence) and 

because no extensive tap roots indicative of deep rooting 

have been observed. The small size of the roots implies 

that the vegetation was of low stature (Retallack and 

Dilcher, 1981); however, the actual size of the plants is 

unknown because no trunks have been found attached to 

these roots. We interpret the leaf remains at the Rose 

Creek locality to largely represent local vegetation (some 

elements may have been transported in) that was 

fossilized approximately in place under conditions of 

rapid sediment deposition, a conclusion in accord with 

that of Retallack and Dilcher (1981) and Farley and 

Dilcher (1986). 

FLORISTIC COMPOSITION 

The leaf taxa in the list below occur at the Rose 

Creek locality. The scheme of classification follows 

Takhtajan (1980). This classification was chosen for two 

reasons. First, the classification of Takhtajan (1980) 

produces families that show relatively little variation in 

foliar architecture, while the classification of Cronquist 

(1981) produces families that can be strongly heterogeneous. This is especially pronounced for Laurales, 

which are well represented in the Rose Creek flora. 

Second, the foliar architecture of Chloranthaceae is more 

similar to that of certain Laurales (like Trimeniaceae) 

than that of Piperales, as would be predicted by the 

classification of Takhtajan (1980). All fossils are assigned 

to class, subclass, and order, when possible. Fossils are 

not assigned to subordinal taxa; instead, only the most 

similar modern families are designated. This is because 

(1) no species of fossil leaf examined here has all the 

characters that circumscribe an extant family, (2) published subordinal taxa of Magnoliidae are often heterogeneous with respect to foliar architecture, and 

(3) disagreement exists among authors with respect to 

the subordinal classification of Magnoliidae. When a 

fossil leaf genus shows some similarity to an extant taxon 

but cannot be included because it does not possess one or 

more diagnostic features, it is preceded by a "cf." 

designation. 

Magnoliophyta 

Magnoliopsida 

Magnoliidae 

Magnoliales 

cf. Winteraceae, Degeneriaceae, Eupomatiaceae, and Annonaceae 

New genus A 

Magnoliophyta -Continued 

Magnoliopsida-Continued 

Magnoliidae-Continued 

Laurales 

cf. Chloranthaceae 

Crassidenticulum decurrens (Lesquereux) 

new combination 

DensineNUm kaulii new genus and species 

cf. Amborellaceae, Monimiaceae, Gomortegaceae, Flernandiaceae 

Landonia calophylla new genus and species 

cf. Atherospermataceae, Gomortegaceae, Gyrocarpaceae, Lauraceae, Flernandiaceae, 

and Flortoniaceae 

Pabiania variloba new genus and species 

cf. Lauraceae 

Pandemophyllum new genus 

P. kvacekii new species 

P. attenuatum new species 

P. sp. 

cf. Illiciales 

Longstrethia varidentata new genus and 

species 

Magnoliidae order unknown; magnoliid-grade 

foliage 

Didromophyllum basingerii new genus and 

species 

Acritodromum ellipticum new genus and 

species 

Reynoldsiophyllum nebrascense new genus 

and species 

Dicotylophyllum angularis new species 

New Genus B 

Rosidae order unknown 

Anisodromum wolfei new genus and species 

Citrophyllum doylei new species 

Magnoliopsida subclass unknown 

Dicotylophyllum myrtophylloides new 

species 

D. rosafluviatilis new species 

D. aliquantuliserratum new species 

D. expansolobum new species 

Magnoliidae and magnoliid-grade foliage are by far 

the most important angiospermous element at Rose 

Creek, comprising 70% of the angiospermous species 

and over 90% of the collected angiospermous specimens. 

Rosidae and incertae sedis comprise 10% and 20% of 

the species, respectively, and each species in these categories is represented by fewer than 10 specimens. This 

situation contrasts with that for most of the classic 

"Dakota sandstone" leaf assemblages reported by 

Lesquereux (1892), where Flamamelididae are a conspicuous and abundant element. Among latest Albian to 

middle Cenomanian leaf megafloras, the dominance of 

Floristic Composition 7 
Magnoliidae and magnoliid-grade foliage at Rose Creek 

is most comparable to the situation for an undescribed 

leaf assemblage from Zone III (Cenomanian) of the 

Potomac Group of Maryland (the Malden Mountain 

assemblage of Wolfe and Upchurch, 1987b), which also 

comes from fine-grained facies. 

The relationship of Rose Creek leaves to extant 

taxa is highly generalized, as might be expected during 

the early phases of angiosperm diversification. Although 

most species can be compared with an extant subclass, 

only half the species possess a suite of features that 

permits placement within an extant order. Further, 

practically no species possesses the full suite of features 

that circumscribes an extant family. This contrasts 

markedly with the situation for the late Paleocene and 

Eocene, 40 million years further into the adaptive 

radiation of flowering plants; at this time, most species of 

leaves have foliar architecture comparable to that of 

extant families. (See, for example, Wolfe, 1977, and 

Hickey, 1977.) The high percentage of extinct taxa 

relative to better known Tertiary leaf megafloras gives 

the Rose Creek flora a strongly archaic aspect. 

EVOLUTIONARY CONSIDERATIONS 

The high relative diversity of Magnoliidae at Rose 

Creek and good quality of preservation provide an 

opportunity to evaluate the evolutionary status of Magnoliidae during the early to middle Cenomanian, 

especially when other reports of Magnoliidae and leaf 

megafossils preserved only as impressions are taken into 

account. From a taxonomic standpoint, the Rose Creek 

assemblage indicates that the "core" alliance of Magnoliidae was well established by the Cenomanian: definite 

representatives of Magnoliales and Laurales occur, as 

well as one species with many points of resemblance to 

Illiciales. However, much variation exists between each 

of the three ordinal alliances in the degree to which 

individual species can be compared with modern 

families. Magnoliales, which are considered the most 

primitive order of flowering plants by Cronquist (1968, 

1981) and Takhtajan (1969, 1980), are represented by 

fossils that show relatively low comparability with a single 

extant family and that show closest similarities to 

generally primitive extant taxa. For example, new genus 

A has the multistranded midrib and low venational 

regularity inferred to be primitive for the flowering plants 

as a whole (Hickey and Wolfe, 1975; Hickey and Doyle, 

1977), plus a combination of features that is most similar 

to generalized magnolialean venation. "Ficus" macrophylla, a taxon originally described by Lesquereux (1892) 

from the Dakota Formation of Kansas, appears to 

represent a Late Cretaceous relative of the Ficophyllum 

complex, whose closest modern affinities lie with the 

primitive families Austrobaileyaceae, Magnoliaceae, and 

Winteraceae (Upchurch, 1983). The closest similarities 

found between an early Cenomanian megafossil taxon 

and an extant family of Magnoliales are those seen 

between the Liriophyllum-Archaeanthus complex and 

extant Magnoliaceae (Dilcher and Crane, 1984). Here, 

certain derived features indicate a possible close cladistic 

relationship, in particular the presence of a calyptra on 

the flowers. However, the overall floral structure of 

Archaeanthus is more primitive than that in Magnoliaceae, while foliar architecture in Liriophyllum is in some 

respects more advanced: each leaf is characterized by a 

primary vein that runs to the leaf apex and dichotomizes, 

a characteristic unknown in any extant Magnoliidae. 

Fossil Laurales provide a marked contrast to fossil 

Magnoliales in comparability to extant families and 

inferred level of advancement. Although Laurales are 

thought to represent a more derived taxon than Magnoliales (Takhtajan, 1980; Cronquist, 1981), certain early 

Cenomanian Laurales can be compared closely with a 

single modern family (Chloranthaceae or Lauraceae ), 

and members of the order as a whole show modern 

affinities that range from primitive to derived. For 

example, Crassidenticulum decun-ens shows close similarities to extant Chloranthaceae (considered one of the 

primitive families of Laurales by Takhtajan [1980]), 

although its precise combination of venational features is 

not known from any extant genus. This is not surprising, 

because dispersed pollen and flowers comparable to 

extant genera of Chloranthaceae occur in older rocks 

(Walker and Walker, 1984; Friis and others, 1986). 

Landonia provides a possible evolutionary link between 

extant primitive Laurales that produce inaperturate 

pollen (Amborellaceae and Monimiaceae) and more 

derived members of the alliance because it combines 

(1) the pinnate venation and generally isodiametric intercostal regions characteristic of Amborellaceae and Monimiaceae, and (2) the generally transverse and sparsely 

branched intercostal tertiary venation with admedial 

branches characteristic of Gomortegaceae and certain 

Hernandiaceae (Illigera). Landonia, therefore, provides 

paleobotanical evidence in favor of the relationship 

postulated between Monimiaceae and Gomoregaceae on 

the basis of comparative morphology (Takhtajan, 1980). 

Cocculophyllum, Pabiania, and Pandemophyllum show 

their closest similarities to Lauraceae and allied families, 

and these three genera together can be interpreted as a 

series of related taxa that shows increasing similarity to 

extant Lauraceae in higher order venation and stomatal 

structure. Assuming that the remains examined in the 

course of our study comprise a representative sample, 

forms comparable to modern families apparently 

appeared much more rapidly in Laurales than in Magnoliales. Of course, much of this pattern also could reflect 

major diversification of Magnoliales in regions outside of 

North America, a concept consistent with the restriction 

8 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
to the Southern Hemisphere of certain advanced magnolialean pollen types, most notably permanent tetrads that 

have been compared to those of extant Winteraceae 

(Walker, Brenner, and Walker, 1983). 

Illiciales are the only core order of Magnoliidae 

whose presence during the early Cenomanian is 

uncertain. Although dispersed cuticle similar to that of 

exta.nt Illiciales occurs as early as late Aptian-early 

Albian (Upchurch, 1984), no known species of Cenomanian age has all the features characteristic of the 

modern order. Longstrethia has a combination of stomatal features that today is restricted to Illiciales (round 

stomata over 30 microns in length, curved lamellar 

cuticular thickenings on the guard cells, T -pieces, and 

laterocytic subsidiary cells), but pronounced striations on 

the c~ticle are absent, and the venation is more poorly 

orgamzed than that of extant Illiciales. This could simply 

reflect the small number of Cenomanian leaf taxa that 

ar~ known in detail but is consistent with palynological 

evidence for the origin of Illiciales much later in the 

Cretaceous (Muller, 1981, 1984). 

Most foliage from Rose Creek cannot be confidently assigned to an extant order. For certain taxa, 

such as Dicotylophyllum angularis, (1) this could be an 

artifact of incomplete preservation, and in particular the 

absence of preserved higher order venation and welldefined cuticular features. For other taxa, such as new 

?enus B, (~) this ~ay be the result of having highly 

Irregular fohar venation with few or no obviously derived 

features. For some taxa, however, this situation results 

from having (3) a combination of features not observed 

in extant angiosperms, or ( 4) one or more foliar 

architectural features not found in extant angiosperms. A 

good example of situation 3 is Acritodromum which 

combines secondary venation that is irregular i~ course 

~nd spaci?g with curved tertiary venation that is highly 

Irregular m course and spacing but tends to be oriented 

parallel to the midvein. The prime example of situation 4 

is Didromophyllum, where the primary veins give rise to 

secondary veins only on their apical sides, and the primary venation plays no role in defining planes of bilateral 

symmet~y within the lamina. These last two examples, 

~long With others provided by latest Cretaceous MagnoliIdae (Upchurch and Wolfe, 1987a), indicate that extant 

Magnoliidae possess only a subset of the variation in 

foliar architecture that once existed within the subclass. 

Within Rosidae, the two species present at Rose 

Creek show a level of advancement comparable to that 

found in early Cenomanian Rosidae as a whole (see data 

provided in Hickey, 1978), and each of the two species 

has features of foliar architecture that today are 

restricted to separate orders. Anisodromum, which 

comprises leaflets with slightly asymmetric secondary 

venation, has well-organized secondary and tertiary venation, a syndrome of features first seen in leaves of late 

Albian age (Hickey, 1978). Citrophyllum, which comprises simple leaves with morphological evidence of a 

compound-leaved ancestry (Hickey, 1978), has one of its 

oldest occurrences at Rose Creek. Both genera possess 

the thin, closely spaced, admedially oriented tertiary 

venation characteristic of extant simple-leaved orders, 

such as Rhamnales, Cornales, and Celastrales, rather 

than the thicker, more widely spaced, transverse tertiary 

venation characteristic of compound-leaved orders such 

as Sapindales and Rutales. This combination of fundamentally compound organization with tertiary venation 

most characteristic of simple-leaved Rosidae provides 

direct fossil evidence for a phylogenetic link between the 

two major divisions of Rosidae (Hickey and Wolfe, 

1975), as predicted by comparative morphology. 

Comparison of Rose Creek species of Rosidae with 

both late Albian rosid foliage (Sapindopsis) and extant, 

simple-leaved taxa of Rosidae such as Rhamnaceae 

indicates that the Rose Creek species occupy the middle 

region of a graded morphological series. One end starts 

wit~ compound-leaved forms belonging to Sapindopsis, 

which possess (1) festooned brochidodromous secondary 

venation where each secondary vein shows eucamptodromous tendencies by forming its own series of brochidodromous loops, and (2) irregular tertiary venation that 

tends to be reticulate and admedially oriented. The other 

end of the series consists of simple-leaved taxa such as 

Rhamnaceae (especially the genera Berchemia and 

Rhamnidium ), Celastraceae (Bhesa), and Olacaceae 

(Coula), which possess (1) truly eucamptodromous 

secondary venation, and (2) thin, closely spaced, percurrent, admedially oriented tertiary venation. The Rose 

Creek species combine the fundamentally compound 

organization characteristic of Sapindopsis with the 

eucamptodromous secondary venation characteristic of 

most simple-leaved rosids, and the tertiary venation 

present in the Rose Creek species is similar to that of the 

simple-leaved rosids but has more irregular organization. 

Sapindopsis has the most irregular vein organization of 

all taxa in the series, which implies that it represents the 

primitive end; this implies that compound leaves are 

primitive to many simple-leaved clades of Rosidae. 

Combined stratigraphic and phenetic evidence reinforces 

evidence from comparative morphology, because pinnately compound foliage of the Sapindopsis type is the 

most ancient and shows the closest morphological 

resemblance to angiosperm leaf taxa of Aptian to middle 

Albian ~ge (Doyle and Hickey, 1976; Hickey and Doyle, 

1977; Hickey, 1978; Upchurch, 1984). 

ECOLOGICAL CONSIDERATIONS 

From an ecological standpoint, the Rose Creek 

flora provides the oldest well-documented occurrence of 

early angiosperms in brackish-water facies and indicates 

Ecological Considerations 9 
that angiosperms tolerated higher-than-freshwater salinities early in their evolutionary history (Retallack and 

Dilcher, 1981, 1985). Taphonomic evidence indicates 

that most Rose Creek taxa probably represent brackishwater plants, rather than the remains of freshwater plants 

transported into brackish-water environments. Most 

leaves were deposited whole and occur in a sequence of 

rooted mudstones in which the leaves can form dense 

mats separated by thicker intervals of barren sediment. 

This pattern implies that many of the leaf-bearing layers 

may represent leaf litter fossilized by the rapid and 

episodic deposition of overbank sediments. The small 

average leaf size of the Rose Creek flora relative to 

coeval assemblages from the Dakota Formation and 

elsewhere (Wolfe and Upchurch, 1987b) corroborates 

taphonomic evidence for brackish-water vegetation. In 

plants, saline habitats produce water stress similar to that 

of dry climates (Walter, 1973), which selects for small 

xeromorphic foliage (Walter, 1973; Givnish, 1979). 

Consideration of the Rose Creek flora in conjunction with evidence on Cenomanian paleoenvironments in the Western Interior indicates that the closest 

modern analogue may be tropical vegetation that occurs 

inland from mangrove swamps in regions of low tidal 

amplitude but which lives under brackish conditions 

(Richards, 1952). First, the diversity of species and 

genera at Rose Creek is high relative to most extant 

mangrove swamps, which are characterized by a few 

species that form monodominant stands, but the diversity 

is similar to that of more inland brackish-water swamps 

(Richards, 1952). Second, biological and physical evidence indicates that the eastern margin of the Western 

Interior sea had very low tidal amplitudes, probably less 

than one meter (Kauffman and Ryer, 1980; Ryer and 

Kauffman, 1980); hence, there was probably little tidal 

dispersal of propagules, as occurs in extant mangroves 

(Richards, 1952). Third, the Western Interior seaway had 

lower salinity than the open ocean during the middle 

Cenomanian, especially in nearshore regions, as indicated by the following: (1) the dominance of agglutinated 

foraminifera in the Graneros Shale of Kansas (Eicher, 

1965), (2) distributional patterns in Cenomanian calcareous nannofossils (Watkins, 1985), and (3) isotopic ratios 

indicative of significant freshwater input into the Western 

Interior sea (Pratt, 1985). Fourth, the molluscan assemblage from Rose Creek consists almost solely of Brachidontes, an assemblage type inferred to represent conditions of low marine influence (Siemers, 1976). More 

fully marine molluscan assemblages occur in the Dakota 

Formation 13 miles downdip to the northwest, less than 

20 m stratigraphically above the Rose Creek locality 

(Veatch, 1969). 

KEY TO LEAF TYPES AT ROSE CREEK 

The determination of leaf types found at Rose 

Creek can be made using the following key. 

la. Primary venation consisting of two veins that run 

along the basal margins of the lamina and give rise to 

secondary veins only on their apical sides-Didromophyllum basingerii 

lb. Primary venation always with a medial vein that 

gives rise to secondary veins on both sides-Go to 2 

2a. Margin entire-Go to 8 

2b. Margin non-entire, either serrate or crenate-Go 

to 3 

3a. Teeth typically less than 2 mm wide, usually visible 

only under magnification-Go to 4 

3b. Teeth greater than 2 mm wide, easily visible to the 

naked eye-Go to 5 

4a. Primary venation palmate, lamina lobed, teeth 

widely spaced-Dicotylophyllum expansolobum 

4b. Primary venation pinnate, lamina unlobed, teeth 

closely spaced-Dicotylophyllum aliquantuliserratum 

Sa. Lamina broadly deltoid, secondary veins straight 

and usually running directly into teeth, secondary veins in 

the basal part of the lamina often basally branched for at 

least half their length-Dicotylophyllum rosafluviatilis 

5b. Lamina elliptic to oblong and usually elongate, 

secondary veins apically curved or connecting with an 

intramarginal vein before entering teeth, lacking tendencies for basal branching-Go to 6 

6a. Teeth few ( < 10) per leaf, strongly asymmetrical, 

secondary venation pinnate with an intramarginal veinLongstrethia varidentata 

6b. Teeth many per leaf, tending toward symmetrical 

and crenate, secondary venation looping and/or curving 

apically before entering teeth-Go to 7 

7a. Teeth < 2 mm wide, secondary veins thin, enclosing 

exmedially elongate intercostal regions-Crassidenticulum decurrens 

7b. Crenations 2-6 mm wide, secondary veins of moderate thickness, enclosing somewhat elongate to isodiametric intercostal regions-Reynoldsiophyllum nebrascense 

Sa. Lamina predominantly 3-lobed to occasionally 

unlobed, lobed forms with suprabasal palinactinodro10 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
mous primary venation and sinuses braced by a lateral 

vein that originates from the midvein and bifurcates at 

the sinal margin, basilaminar secondary veins strongly 

developed in all specimens-Pabiania variloba 

8b. Lamina always unlobed, venation always pinnate, 

basilaminar secondary veins weakly developed or 

absent-Go to 9 

9a. Lamina showing evidence of leaflet homology, 

either by having secondary veins that originate at lower 

angles on one side of the midrib or by having an alate 

petiole that is constricted at the base of the lamina, 

secondary venation tending towards eucamptodromous-Go to 10 

9b. Lamina showing no evidence of leaflet homology, 

secondary venation festooned brochidromous or pinnate 

with an intramarginal vein-Go to 11 

lOa. Petiole alate and constricted at base of lamina, 

secondary veins truly eucamptodromous (not forming 

loops near margin), originating at similar angles on both 

sides of the midrib-Citrophyllum doylei 

lOb. Petiol(ule) not alate, secondary veins forming 

some loops near the margin, originating at slightly lower 

angles on one side of the midrib-Anisodromum wolfei 

lla. Brochidodromous loops flattened at least in the 

apical regions of lamina, in some species forming a 

well-developed intramarginal vein-Go to 12 

llb. Brochidodromous loops not flattened, no intramarginal vein present-Go to 17 

12a. Lamina strongly oblong in shape, intramarginal 

vein well developed for full length of lamina, tertiary 

venation reticulate and irregular in behavior, unoriented 

to somewhat admedially oriented-Go to 13 

12b. Brochidodromous loops flattened in the apical 

regions of lamina and sometimes in other regions but not 

forming a full-fledged intramarginal vein, tertiary venation unbranched to reticulate and tending towards transverse-Go to 14 

13a. Laminar width ~1 em, intercostal regions apically elongate-Dicotylophyllum myrtophylloides 

13b. Laminar width 1-2 em, intercostal regions exmedially elongate to isodiametric-Longstrethia varidentata 

14a. Lamina probably obovate, brochidodromous 

looping highly angular, tertiary venation strongly 

reticulate, with lateral branches of the tertiary veins 

gradually thinning, anastomosing, and giving rise to 

reticulate quaternary veins-New genus A 

14b. Lamina elliptic to ovate, brochidodromous 

looping tending towards curved, tertiary venation often 

unbranched and with a well-developed transverse component, quaternary venation tending to be distinct and 

consisting of unbranched to admedially branched veinsGo to 15 

15a. Lamina strongly ovate, with elongate attenuate 

apex-Pandemophyllum attenuatum 

15b. Lamina elliptic to oblong, apex (when preserved) 

acute-Go to 16 

16a. Lamina elliptic to slightly ovate or obovate, L/W 

ranging from 2-3, each secondary vein in the basal 

two-thirds of lamina forming its own series of excostal 

loops-Pandemophyllum kvacekii 

16b. Lamina oblong, L/W probably well over 3, some 

secondary veins in the basal two-thirds of lamina forming 

flattened brochidodromous arches-Pandemophyllum 

sp. 

17a. Each secondary vein forming its own series of 

apically arching excostal loops, margin with serrations 

visible only under magnification-Dicotylophyllum aliquantuliserratum 

17b. Each secondary vein forming excostalloops, these 

loops not forlll;ing clearly defined series, margin 

entire-Go to 18 

18a. L/W of intercostal regions 5-6, inner series of 

excostal loops exmedially elongate and rounded on the 

outer side-Densine1VUm kaulii 

18b. L/W of intercostal regions less than 3, inner series 

of excostalloops irregular in shape-Go to 19 

19a. Lamina oblong, inner series of excostal loops 

tending to join margin-Go to 21 

19b. Lamina elliptic to ovate, inner series of excostal 

secondary loops not tending to join margin-Go to 20 

20a. Secondary veins with highly irregular spacing and 

angles of origin, not making a distinctively sharp bend 

before looping, tertiary veins highly irregular in course 

and spacing but oriented 135°-180° to midrib-Acritodromum ellipticum 

20b. Secondary veins with relatively regular spacing 

and angle of origin, making a sharp bend just before 

looping, tertiary venation not strongly oriented-Dicotylophyllum angularis 

21a. Lamina <1 em wide, intercostal tertiary venation 

highly irregular in behavior-New genus B 

Key to Leaf Types at Rose Creek 11 
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I 

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\ 

1 

l 

\ 

l 

l 

I 

I 

I 

I 

I 

Figure 2. New genus A, 15713-4879, specimen shown on plate 1. A, General view of leaf, x 1. 

8, Tertiary and higher order venation, x 7.5. On the primary vein, only the vascular strands nearest 

the secondary veins have been drawn. 

21b. Lamina 4-5 em wide, intercostal tertiary venation 

tending to enclose transversely elongate regions-Landonia ca/ophylla 

SYSTEMATICS 

Class MAGNOLIOPSIDA 

Subclass MAGNOLIIDAE 

Order MAGNOLIALES 

New genus A 

Plate 1, figures 1-4; text figure 2 

Description.-Basal part of lamina preserved, L/W 

estimated to be over 1.5, lamina greater than 7 em long 

by 4.6 em wide (estimated width); apex and base 

unknown; margin entire, slightly sinuate under magnification, with mechanical reinforcement (nature of tissue 

unknown). Primary venation pinnate; primary vein stout, 

multistranded. Secondary venation irregularly brochidodromous; secondary veins thin relative to primary vein, 

more than 7 pairs, subopposite, somewhat irregularly 

spaced, decurrent on the primary vein, originating at a 

moderate acute angle, zig-zag in course and often slightly 

recurved just below junction with superadjacent 

secondary vein; both secondary veins of equal thickness 

at their junction and with the superadjacent secondary 

vein deflected apically, angle of junction strongly obtuse, 

brochidodromous arches flattened. Excostal tertiary 

venation poorly differentiated from secondary venation, 

irregularly looped. Excostal quaternary venation poorly 

differentiated from excostal tertiary venation, similar in 

behavior but forming smaller loops that tend to be 

strongly flattened. Intersecondary veins common, one 

per intercostal region, arising decurrently from primary 

vein and branching to form tertiary veins. Intercostal 

tertiary venation reticulate; tertiary veins thick relative to 

secondary veins, originating at variable angles but 

tending toward right -angled, irregular in course but 

tending toward transverse, enclosing roughly rectangular 

areas, producing thinner, non-orthogonal lateral 

branches that ramify, anastomose, and eventually thin 

into quaternary veins. Ultimate venation poorly preserved, possibly with freely ending veinlets. Marginal 

venation poorly preserved, either with a fimbria! vein or 

loops associated with mechanical tissue. Resin bodies 

present, interpreted as the remains of mesophyll secretory cells. 

Cuticle not well preserved, no preparations made. 

Number of specimens examined.-!. 

Specimen number.-15713-4879. 

Discussion.-New genus A is recognized on an 

informal basis because of fragmentary preservation. 

Despite this, New genus A clearly is distinct from all 

previously described taxa of Cretaceous angiosperm 

leaves. Among previously described taxa, New genus A 

resembles one specimen of "Juglans" debeyana Heer 

12 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
from the Dakota Formation of Kansas (Lesquereux, 

1874, pl. 23, fig. 3), especially in the shape of the 

intercostal regions, angle of secondary vein origin, and 

pattern of tertiary venation, but it differs in having a 

much thicker midrib and a more uniform pattern of 

secondary vein branching. New genus A also resembles 

"Ficus" macrophylla from the Dakota Formation of 

Kansas (Lesquereux, 1892, pl. 11, fig. 1) in overall 

appearance, the shape of its intercostal regions, and 

pattern of tertiary venation but differs in having a much 

smaller size, better defined intercostal regions, and more 

regular pattern of secondary vein branching. Finally, New 

genus A resembles Ficophyllum crassine1Ve Fontaine 

from the Potomac Group (Fontaine, 1889, pis. 144-148) 

and similar species ("Ficus" virginiensis Fontaine, Proteaephyllum ovatum Fontaine, and certain specimens 

referred to Ficophyllum tenuine1Ve Fontaine) in general 

features, but it differs in having a more regular pattern of 

secondary vein looping, more obtuse angle of junction 

between adjacent secondary veins, intersecondary veins 

in every intercostal region, and thicker, more irregular 

tertiary and quaternary venation. 

New genus A is inferred to represent an extinct 

taxon within Magnoliales, some extant members of which 

are illustrated on plate 2. An affinity to Magnoliidae is 

indicated by the high irregularity of the venation, the 

poor distinction of vein orders, and the presence of 

mesophyll resin bodies, which may be the remains of 

oil-filled cells. Within Magnoliidae, New genus A 

possesses a suite of features that characterizes several of 

the more primitive taxa within Magnoliales, including 

Winteraceae, Degeneriaceae, Magnoliaceae, and certain 

Annonaceae (pl. 2). These features include (1) an entire 

margin, (2) brochidodromous secondary venation that is 

zig-zag in course and encloses straight -sided, nearly 

symmetrical intercostal regions, (3) abundant intersecondary veins that branch to form tertiary veins and never 

number more than one per intercostal region, and 

( 4) reticulate tertiary venation that has a tendency for 

transverse orientation, encloses predominantly rectangular areas, and gives rise to somewhat thinner, nonorthogonal lateral branches that eventually become 

quaternary veins. The probable obovate shape of New 

genus A is consistent with these other characters, 

because Magnoliales differ from other orders of Magnoliidae in showing strong tendencies for obovate leaf 

shape. Within the above group of families, New genus A 

most closely resembles Winteraceae in having a multistranded primary vein, irregularly spaced secondary veins 

that form a strong obtuse angle at their junction (for 

example, Zygogynum (pl. 2, fig. 5)), and marginal venation that consists of flattened brochidodromous loops. 

However, New genus A falls outside the range of 

variation shown by Winteraceae in having less decurrent 

secondary venation than is typical for the family and in 

having a slightly sinuate margin with well-developed 

mechanical tissue. Of the similarities shared with Winteraceae, none provides unambiguous evidence of a close 

relationship: the multistranded primary vein and 

irregular secondary venation are inferred to be primitive 

for the dicotyledons as a whole (Wolfe and others, 1975; 

Hickey and Doyle, 1977), and flattened brochidodromous loops occur in other families of Magnoliales, such 

as Annonaceae. New genus A and Winteraceae probably 

retain numerous features that were present in the 

common ancestor of Magnoliales, rather than derived 

features indicative of a close relationship. 

Order LAURALES 

Crassidenticulum new genus 

Diagnosis.-Lamina elliptic to oblong; petiole with 

a decurrent wing of laminar tissue; margin predominantly non-entire, with numerous very small teeth 

that possess well-developed mechanical thickening along 

the margin; tooth construction of the chloranthoid type. 

Primary venation pinnate; primary vein stout to massive. 

Secondary venation showing strong craspedodromous 

tendencies but with the secondary veins curving apically 

and tending to form loops on the superadjacent 

secondary veins before entering teeth; secondary veins 

thin relative to the primary vein, numerous, closely 

spaced. Intersecondary veins present. Tertiary venation 

reticulate, not rigidly organized. Higher order venation 

irregularly reticulate. 

Type species.-Celastrophyllum decurrens Lesquereux, 1892, p. 172, pl. 36, fig. 1-see pl. 4, fig. 1 of 

this report for a photograph of the holotype. 

Derivation of name.-Latin, crassus =thick, 

denticulum =diminutive of tooth, referring to the welldeveloped structural reinforcement on the small teeth. 

Crassidenticulum decurrens (Lesquereux) new combination 

Plate 3; plate 4; text figure 3 

Celastrophyllum decwrens Lesquereux, 1892, p. 172, pl. 36, fig. 1 

Diagnosis.-As for genus. 

Description.-Lamina narrowly elliptic to oblong, 

L/W 4-6, leaf 3-13 em long by 0.5-4 em wide; apex 

attenuate; base decurrent and occasionally flared immediately above petiolar region; petiolar region with a 

decurrent wing of laminar tissue; margin ranging from 

finely serrate to crenulate, often on the same leaf, very 

rarely entire; serrations and crenations approximately 

1 mm wide by less than 1 mm tall, serrations typically 

straight-convex (B-1), intergrading with convex-convex 

Systematics 13 
Figure 3. Crassidenticulum decurrens (Lesquereux) new combination. A and 8, 15713-4730, specimen shown on 

plate 3, figures 1-3. A, Drawing of whole specimen, x 3. The midrib consists of three groups of coalesced vascular 

strands that separated when the leaf decayed. 8, Details of margin, x 7.5. Stippled regions designate areas where the 

remains of the structural reinforcement have pulled away from the leaf. C, 15713-4746, specimen from plate 4, figure 

6, higher order venation, x 7.5. The drawing of the midrib is schematic and only intended to show groups of vascular 

strands. 

(A-1) crenulations. Primary venation pinnate; primary 

vein stout to massive, appearing to be multistranded in 

partially decayed specimens. Secondary venation fundamentally craspedodromous, but with the secondary veins 

curving apically and tending to form loops with the 

superadjacent secondary veins before entering teeth; 

secondary veins thin, numerous, closely spaced, decurrent on the primary vein and sometimes also giving off a 

decurrent branch just above the point of origin, diverging 

at predominantly narrow to moderate acute angles, 

showing an irregular pattern of variation in divergence 

angle, irregular to nearly regular in course, generally not 

much curved until at least halfway to margin, tending to 

form festooned brochidodromous loops on the superadjacent secondary veins, angle of the junction between 

secondary veins ranging from acute to obtuse, loops 

angular to rounded, excostal branches of the secondary 

veins either forming loops or running to the margin. 

Intersecondary veins common, mostly 1-3 per intercostal 

region, either arising from primary vein or arising from 

the exmedial side of secondary veins, intergrading with 

the secondary veins, irregular in course, either branching 

to form tertiary veins or joining with the secondary veins. 

Tertiary venation reticulate, often obscure; tertiary veins 

thick relative to the secondary veins, diverging at highly 

variable angles, course and spacing irregular but showing 

some tendency towards admedial orientation. Quaternary venation generally obscure or not preserved, 

irregularly reticulate; quaternary veins often curved. 

Areoles small, under 0.3 mm in diameter, somewhat 

variable in size and shape. Serrations glandular, conforming to the chloranthoid type of Hickey and Wolfe 

(1975), with a prominent, often thickened gland and a 

pair of accessory veins that run along the margin and fuse 

with the gland; crenulations tending toward nonglandular but with a similar arrangement of veins, usually 

with a zone of thickening that extends along the full width 

of the tooth. Thickening probably composed of scelerenchyma rather than vascular tissue, based on its tendency 

to be darker and show more relief than veins on the same 

leaf. 

Cuticle poorly preserved, no successful preparations made. 

Number of specimens examined.-> 100. 

Holotype.-University of Kansas State Museum 

(UKSM) 7257. 

Hypotypes.-15713-4723, 4728, 4730, 4732, 4732', 

4746,4795a,4938, 7817,7818. 

Discussion.-Pinnately veined, serrate-margined 

angiosperm foliage of Cretaceous age typically has been 

assigned to Celastrophyllum Goeppert, a form genus for 

leaves belonging to Celastraceae. However, this assignment appears to be invalid, at least for mid-Cretaceous 

leaves. The type species, Celastrophyllum attenuatwn 

(Goeppert, 1854, p. 52, pl. 14, figs. 89, 91), is described 

and illustrated as having an entire margin and a 

14 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Figure 4. Ascarina /anceolata Hook f., U.S.G.S. Ref. Coli. no. 2327. A, 

Apical region of leaf, x 3. 8, Details of teeth along lower right margin, x 7.5. 

Dotted region at the apex of each tooth designates differentially staining 

tissue. 

distinct petiole. This combination of features is not 

present in the mid-Cretaceous species of Celastrophyllum 

examined by us, nor is it present in extant species of 

Celastrus. In extant angiosperms, margin type and petiolar construction typically separate genera and higher 

taxa. The discrepancy between the morphology of the 

type species and mid-Cretaceous remains has, in practice, been alleviated by many authors through expanding 

the concept of Celastrophyllum to include both entireand non-entire-margined foliage with a general relationship to Celastraceae. This expansion of generic concept 

would appear logical, because extant Celastraceae range 

from entire-margined to toothed; however, the midCretaceous species of Celastrophyllum examined by us do 

not possess features diagnostic of extant Celastraceae. 

Features missing from mid-Cretaceous foliage that 

diagnose extant Celastraceae include a distinct petiole, 

teeth with a glandular, non-deciduous seta directed into 

the sinus (a celastroid tooth), and subparallel tertiary 

venation with low-angle branching and perpendicular 

orientation to the midvein. Many individual species of 

Celastrophyllum differ from one another in features that 

typically segregate extant genera and families, including 

tooth construction, presence or absence of a structurally 

reinforced margin, size and structure of the primary vein, 

pattern of secondary venation, and details of tertiary and 

higher order venation. Thus, more than one genus is 

needed to accurately reflect the systematic relationships 

of pinnately veined, serrate-margined foliage traditionally assigned to Celastrophyllum. 

Among other previously described genera that 

circumscribe only fossil leaves, none closely resembles 

the Rose Creek remains when comparison is restricted to 

the type species and similar forms. Quercophyllum Fontaine shows the closest resemblance, but the type species, 

Q. grossidentatum (Fontaine, 1889, pl. 156, fig. 9), has 

significantly larger teeth, no marginal thickenings, and a 

strongly attenuated primary vein. 

Among previously described species of Cretaceous 

angiosperms that have incorrect generic assignments, C. 

decurrens shows similarities with many species but 

represents a distinct taxon. C. decurrens most closely 

resembles "Myrica" zenkeri (Ett.) Heer, illustrated in 

photographs by Vakhrameev (1952, pl. 11, figs. 1, 2; pl. 

41, fig. 1), in laminar size and shape, the size and shape 

of the teeth, and the presence of strongly developed 

marginal thickenings over the teeth. However, all 

photographically illustrated specimens of "M." zenkeri 

have no venation visible above the first order, making 

determination of conspecificity of C. decurrens and "M." 

zenkeri impossible. C. decurrens closely resembles "Myrtophyllum" torreyi (Lesquereux) Dorf, such as specimens 

photographically illustrated by Brown (1962, pl. 50, 

figs. 1-4, 7-9), in nearly all preserved features but differs 

in having secondary veins that arch apically and directly 

enter the teeth, rather than connect with an intramarginal 

vein. Thus, while the two species may be congeneric, they 

are distinct. Crassidenticulum decurrens also resembles 

Celastrophyllum hunteri Ward from the Potomac Group 

of Virginia (Ward, 1905, pl. 4, fig. 9) in having a 

Systematics 15 
Table 1. Comparison of Crassidenticulum, Densinervum, and related extant taxa 

[NA. =not applicable] 

Taxon 

Crass i dent i cu l um 

Dens i nervum· ·---

~--------

Hedyosmum· ·-----

Chloranthus····· 

~-------

~--------

Piptoca lyx·-- ·--

Midvein 

Mul tistranded·-

Solid····------

5 to 7-stranded 

at base of 

lamina. 

Usually 3· to 

5-stranded at 

base, multi· 

stranded at 

base in one sp. 

5 ·stranded 

at base 

of lamina. 

5-stranded 

at base 

of lamina. 

3-stranded 

or coalesced 

strands. 

5-stranded-----

Secondary 

venation 

Fundamentally 

craspedodromous, 

but with tendency 

to form loops and/ 

or curve apically. 

Festooned 

broch idi dromous. 

Fundamentally 

craspedodromous, 

but with tendency 

to form loops 

and curve apically. 

Fundamentally 

craspedodromous, 

usually curved 

apically. 

Festooned 

broch i dodromous. 

Festooned 

broch i dodromous. 

Usually pinnate 

with an intra· 

marginal vein, 

!. simple eras· 

pedodromous in 

!· papuana. 

Pinnate with intra· 

marginal vein. 

Inter· 

secondary 

veins 

Common, 

originate from 

mi dvei n or 

secondary 

veins. 

Common, 

originate from 

midvein or 

secondary veins. 

Present in 

some species, 

originate 

from midvein. 

Present in 

some species, 

originate 

from midvein. 

Weakly 

developed 

to absent, 

originate 

from mi dvei n. 

Weakly 

developed 

to absent, 

originate 

from midvein. 

Absent-··------

Absent-·······-

multistranded primary vein, a similar pattern of 

secondary venation, and a thickened, serrate margin, but 

differs in having more closely spaced and more rounded 

teeth that often are thickened only over the gland, and in 

having more strongly craspedodromous secondary venation. Crassidenticulum decurrens shows some similarity to 

two species of Celastrophyllum from the Upper 

Cretaceous Amboy clays of New Jersey, C. angustifolium 

Newberry (Newberry, 1895, pl. 14, figs. 11, 12, 14-16) 

and C. crenatum Heer (Berry, 1911b, pl. 22, fig. 9), 

especially in the size and shape of the lamina, pattern of 

secondary venation, and the size of the teeth, but it differs 

in having more regular and fundamentally craspedodromous secondary venation. Crassidenticulum decurrens 

resembles "Salix" newbenyana Hollick (in Newberry, 

1895, pl. 11, fig. 2) from the Upper Cretaceous of New 

Jersey in its size, shape, and number of intersecondary 

veins, but it differs in having no distinct petiole and in 

having less apically curved secondary venation. Finally, C. 

decurrens resembles ?Rogersia denticulata from the 

Lower Cretaceous of the Soviet Union (Samylina, 1960, 

pl. 1, fig. 10, text fig. 6) in size, shape, and base, but it 

differs in having much smaller teeth and in having more 

apically curved and less obviously craspedodromous 

secondary veins. These similarities indicate that CrassiTertiary 

venation 

Irregularly 

reticulate. 

Irregularly 

reticulate. 

Irregularly 

reticulate, 

often 

exmedially 

oriented. 

Reticulate. 

Transverse 

reticulate. 

Transverse 

reticulate. 

Admedially 

ramified 

and with a 

reticulate 

component. 

Admedially 

ramified. 

Margin 

Finely 

serrate to 

crenate, 

rarely 

entire. 

Entire···-------

serrate········-

Serrate---···---

Serrate-------·· 

Usually serrate. 

usually serrate. 

Entire·-----·-·· 

Tooth 

type 

Chloranthoid··· 

N.A.········ ••• 

Ch l oranthoid, 

sometimes 

with one 

accessory 

vein supressed. 

Ch l oranthoi d---

Chloranthoid·--

Ch l orantho i d·- • 

Monimioid------

N.A. ••••••••••• 

Marginal 

thickening 

over teeth 

Well developed. 

N .A. 

Absent. 

Sc l erenchyma 

over tooth 

apex in some 

species. 

Resistant tissue 

over tooth apex, 

not strongly 

developed as in 

£-~-

Resistant tissue 

over tooth apex, 

not strongly 

developed as in 

£-~-

Absent, but with 

opaque tissue 

over gland. 

N.A. 

denticulum may have been a diverse genus during the 

Late Cretaceous, but detailed consideration of this 

possibility must await revision of other floras. 

The modern affinities of Crassidenticulum appear 

to lie with Chloranthaceae, with additional affinities 

possibly to Trimeniaceae (table 1). The combination of a 

poorly differentiated petiole and blade, a multistranded 

primary vein, irregular secondary and higher order venation, and chloranthoid teeth is restricted to the subclass 

Magnoliidae, and in particular the orders Laurales and 

Illiciales. Between these two orders, fundamentally 

craspedodromous secondary venation is restricted to 

Laurales. Within Laurales, the exact pattern of secondary 

venation found in Crassidenticulum occurs only in the 

chloranthaceous generaAscarina and Hedyosmum (pl. 7, 

figs. 2, 3; text fig. 4), and Trimenia (pl. 7, fig. 1) has a 

related pattern of secondary venation where the craspedodromous secondary veins are interconnected near the 

laminar margin by thinner lateral branches, which form a 

weak intramarginal vein. Among extant Chloranthaceae 

and Trimeniaceae, Crassidenticulum most closely 

resembles Ascarina and Hedyosmum in having closely 

spaced and apically curved secondary veins, common 

intersecondary veins, and small chloranthoid teeth. In 

addition, some species of Hedyosmum have sclerenchy16 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
matous tissue over the apex of each tooth (Richard 

Keating, oral comm., 1988). However, Crassidenticulum 

differs from Ascarina and Hedyosmum in having more 

irregular secondary venation, intersecondary veins that 

can arise either from a primary vein or the admedial side 

of a secondary vein, and irregular tertiary and quaternary 

venation, features postulated as primitive to the angiosperms as a whole (Doyle and Hickey, 1976; Hickey and 

Doyle, 1977). Thus, C. decurrens shows its closest 

similarities with extant Chloranthaceae but appears to 

represent a distinct genus. 

Densinervum new genus 

Diagnosis.-Lamina entire margined; margin with 

mechanical reinforcement; petiolar region distinct from 

lamina. Primary venation pinnate; primary vein moderate. Secondary venation "festooned" brochidodromous; secondary veins thin relative to the primary vein, 

enclosing exmedially elongate intercostal regions that are 

much longer than broad. Intersecondary veins common, 

arising from the primary vein or the exmedial sides of 

secondary veins, typically branching to form tertiary 

veins. Tertiary venation both reticulate and ramified, 

irregular, tending to enclose regions elongate parallel to 

the secondary veins. Quaternary venation irregularly 

reticulate; quaternary veins often curved. 

Type species .-Densinervum kaulii new species. 

Derivation of generic name.-Latin, densus =close, 

and nervis =nerve, referring to the closely spaced secondary veins. 

Densinervum kaulii new species 

Plate 5; text figure 5 

Diagnosis.-As for genus. 

Description.-Lamina ovate and in one specimen 

with a shallow indentation just above the widest part, 

L/W about 1.5-2, lamina approximately 3-5 em long by 

2-3 em wide (estimated length and width); apex missing; 

base obtusely cuneate to rounded; margin entire, with 

structural reinforcement; petiole distinct, but in one 

specimen with a very narrow decurrent wing of laminar 

tissue along one side. Venation pinnate; primary vein 

moderate. Secondary venation "festooned" brochidodromous; secondary veins thin or moderate relative to the 

primary vein, numerous, opposite to alternate, irregularly and very closely spaced (7-8 veins per em), 

sometimes slightly decurrent on primary vein, moderate 

acute, predominantly straight, with only slight undulation 

before looping; secondary veins bifurcating when 

forming loops, angle of brochidodromous junction acute; 

two series of excostal secondary loops present, inner 

series exmedially elongate, with rounded outer sides, 

outer series more or less isodiametric. Intersecondary 

veins common, usually 1-2 per intercostal region, intergrading with both the secondary and tertiary veins, decurrent on primary vein and sometimes originating from the 

secondary veins, generally oriented at an oblique angle to 

the secondary veins and unevenly dividing the intercostal 

region, branching to form tertiary veins or joining with 

the subadjacent secondary vein. Tertiary venation 

predominantly reticulate, but with some tertiary veins 

thinning to form quaternary veins; tertiary veins thick 

relative to the secondary veins, ranging from acute to 

obtuse on both sides of the secondary veins, tending to be 

widely spaced and ad medially oriented. Quaternary venation irregular, curved, similar to tertiary venation in 

behavior; quaternary veins intergrading with the tertiary 

veins and originating from thin branches of the tertiary 

veins. Marginal venation looped, the loops tending to be 

flattened parallel to the margin. 

Cuticle not preserved on specimens. 

Number of specimens examined.-6. 

Holotype.-15713-4841A, 4841A' (part and 

counterpart). 

Paratypes.-15713-4800, 4830, 7815. 

Derivation of epithet.-In honor of Robert B. Kaul, 

and in recognition of his contributions to angiosperm 

phylogeny. 

Discussion.-Densinervum kaulii is readily 

distinguished from all previously described taxa by the 

combination of (1) an entire margin, (2) very closely 

spaced secondary veins, (3) an inner series of exmedially 

elongate excostal loops, ( 4) common intersecondary 

veins that can arise from secondary veins, (5) irregular 

tertiary venation that tends to enclose elongate regions 

parallel to the secondary veins, and (6) curved quaternary venation. D. kaulii most closely resembles Crassidenticulum decurrens in having numerous thin and 

closely spaced secondary veins and a similar pattern of 

tertiary and quaternary venation. In addition, the origin 

of intersecondary veins from the exmedial side of the 

secondary veins is similar to the condition found in C. 

decurrens, where a secondary vein bifurcates shortly 

above its point of origin; this similarity in behavior and 

position implies that the two conditions are homologous. 

D. kaulii differs from C. decurrens in always having an 

entire margin (found on occasional specimens of C. 

decurrens ), an obtusely cuneate to rounded base, a 

distinct petiole, a moderate primary vein, more irregular 

secondary vein looping, and an exmedially elongate inner 

series of excostal secondary loops. Among other 

previously described Cretaceous leaf types, Densinervum 

kaulii resembles entire-margined species of Celastrophyllum from Zone I (Aptian-lower Albian) of the Potomac 

Group such as C. obovatum (Fontaine, 1889, pl. 172, 

figs. 9, 10), C. latifolium (Fontaine, 1889, pl. 172, figs. 3, 

6; pl. 173, fig. 13), and cf. C. obovatum of Upchurch 

Systematics 17 
c 

Figure 5. Densinervum kaulii new genus and species. A, 15713-4880, x3. 8, 15713-4841A, specimen 

shown on plate 5, figures 5 and 6, details of tertiary and higher order venation, x 7.5. The circular stippled 

region designates a fossil root that penetrates the leaf vertically. C, 15713-7815, specimen shown on plate 

5, figure 2, x 7. 

(1984, fig. 6) in shape, primary vein thickness, and angle 

of secondary vein divergence, but it differs in having a 

distinct petiole, in the shape of its excostal secondary 

loops, and in details of tertiary venation. 

The irregular secondary and higher order venation 

of Densinen;um kaulii are most characteristic of the 

extant subclass Magnoliidae. Within Magnoliidae, D. 

kaulii shows no close resemblance to any extant family. 

D. kaulii resembles some Canellaceae (certain species of 

Cinnamodendron) in secondary vein spacing and 

proportioning of the excostal secondary loops.but differs 

in having a distinct petiole, less angular secondary vein 

looping, and less ramified higher order venation, features 

that are fairly uniform within extant Canellaceae. Among 

fossil Magnoliidae, however, D. kaulii closely resembles 

Crassidenticulum decurrens. This close resemblance 

implies a close relationship between the two taxa, which, 

by extension, would imply a relationship with extant 

Chlorathaceae. Thus, Densinen;um kaulii represents an 

extinct taxon that may be related to extant Chloranthaceae but does not have all of the characters that 

circumscribe the extant family. 

Landonia new genus 

Diagnosis.-Leaf oblong; base decurrent; margin 

with mechanical reinforcement. Primary vein stout, multistranded. Secondary venation festooned brochidodromous, with the basalmost pairs of secondary veins closely 

spaced and the superadjacent pairs wider apart; 

secondary veins originating at broad acute or higher 

18 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
angles, tending toward sinuous; intercostal regions 

roughly isodiametric above the basalmost few centimeters of the leaf. Intercostal tertiary venation reticulate, 

consisting of thick, roughly transverse veins that give rise 

to somewhat thinner, admedially oriented lateral 

branches. Excostal tertiary venation admedially ramified. 

Type species .-Landonia calophylla. 

Derivation of name.-In honor of James Landon, 

and in recognition of his contributions to the paleobotany 

of Nebraska. 

Landonia calopbylla new species 

Plate 6, figures 2-5; text figure 7 

Diagnosis.-As for genus. 

Description.-One side of the lamina preserved, 

laminar shape oblong, estimated L/W over 2, lamina well 

over 6.7 em long by about 5 em wide (estimated width); 

apex missing; base strongly obtuse but decurrent at the 

junction with the petiolar region; petiolar region at least 

3 em long; margin entire, with structural reinforcement. 

Primary venation pinnate; primary vein stout, multistranded. Secondary venation "festooned" brochidodromous, with some intracostal branching; secondary 

veins moderate to thick relative to the primary vein, 

possibly multistranded, numbering more than five pairs, 

Figure 6. Gomortega keule (Mol.) Baill. 

(Gomortegaceae), U.S.G.S. Ref. Coli. no. 

2462, leaf from plate 6, figure 1, and plate 7, 

figure 5, x 1.4. To facilitate comparison with 

the specimen in figure 7, only the venation on 

the right side of the leaf is illustrated. 

Figure 7. Landonia calophyl/a new genus 

and species, 15713-4881A, specimen shown 

on plate 6, figures 3-5, x 1.4. Note the 

similarity in tertiary venation to that of 

Gomortega keule, especially the tertiary venation in the uppermost intercostal region. 

irregularly spaced but with the basalmost two pairs very 

close to one another and the others much farther apart, 

these latter secondary veins enclosing roughly isodiametric intercostal regions; secondary veins decurrent on 

the primary vein for a short distance, originating at 

predominantly broad acute, rarely right, angles, with one 

of the secondary veins producing an intracostal branch on 

its admedial side and another of the secondary veins 

producing an intracostal branch on its exmedial side, 

secondary veins often sinuous in course, more strongly 

curved above their junctions with the subadjacent 

secondary veins, looping well within the margin; superadjacent secondary vein deflected apically, usually with 

each secondary vein of roughly equal thickness both 

below and above its junction with the subadjacent 

secondary vein, but in one case with the secondary vein of 

much greater thickness below the junction and appearing 

to bifurcate; excostal branches of the secondary veins 

forming a complete inner series and an incomplete outer 

series of loops, the loops of the inner series either 

confluent with the margin or with a highly irregular 

shape, giving rise to one or more admedial branches per 

loop. Intercostal tertiary venation with two components, 

the thicker component unbranched to reticulate, 

Systematics 19 
moderate to thick relative to the secondary veins, 

originating at predominantly acute to right angles on 

both sides of the secondary veins, subparallel, tending to 

enclose elongate regions, weakly transverse to oblique 

relative to the secondary veins, but in one intercostal 

region with a slight tendency to be admedially ramified; 

the thinner component originating as non-orthogonal 

lateral branches, typically from the admedial side of the 

thicker veins, branching, anastamosing, and eventually 

thinning to form quaternary veins. Tertiary venation of 

excostal secondary loops admedially ramified. Quaternary (and higher order?) venation poorly preserved. 

Small dark spots present on the lamina, interpreted as 

the remains of mesophyll secretory cells. 

Cuticle poorly preserved, no preparations made. 

Number of specimens examined.-1. 

Holotype.-15713-4881A, 4881A' (part and 

counterpart). 

Derivation of epithet.-Greek, kalos =beauty, and 

phyllon =leaf, referring to the beautiful appearance of 

the fossil. 

Discussion.-Despite the fragmentary preservation 

of the one known specimen of Landonia calophylla, 

enough of the foliar architecture is preserved to indicate 

that it represents a distinct genus of Cretaceous angiosperms. The combination of features that distinguishes 

Landonia from all other genera of extant and fossil 

angiosperms includes (1) oblong shape, (2) widely 

spaced secondary veins that have an irregular course and 

enclose roughly isodiametric intercostal regions above 

the base of the lamina, (3) predominantly transverse 

intercostal tertiary venation that produces thinner and 

typically admedial lateral branches, and ( 4) presence of 

admedially ramified tertiary veins in the excostal 

secondary loops. Although these features may occur 

individually in one or more taxa, together they form a 

distinctive suite of features that permit identification of 

leaves even in a fragmentary state. 

In addition, many of the individual venational 

features found in Landonia are unusual in the context of 

extant and fossil dicot leaves. Multistranded secondary 

veins are unknown in extant dicots and all previously 

described Cretaceous angiosperm leaves, even for 

species with multistranded primary veins and extremely 

irregular vein organization. Admedial intracostal 

branching of the secondary veins occurs in scattered 

extant taxa such as Canellaceae ( Capsicodendron) and 

Theaceae (various genera), and in Early Cretaceous taxa 

such as Quercophyllum tenuine!Ve Fontaine (see Hickey 

and Doyle, 1977, figs. 5, 17); however, exmedial intracostal branching of the secondary veins has never been 

observed in any extant or fossil angiosperm. The high 

irregularity in the shape of the excostal secondary loops, 

in conjunction with the production of admedially 

ramified tertiary veins, is atypical of extant dicots, 

although present in the possibly related Gomortegaceae 

(see below). Finally, the high variation found in thickness 

of one secondary vein has no known extant counterpart. 

This secondary vein is significantly thicker than the other 

secondary veins at its point of origin and abruptly thins at 

two points of branching: (1) close to the midrib, where a 

short, stubby, intracostal branch originates on the exmedial side, and (2) at the point of junction with the 

subadjacent secondary vein, where the thick secondary 

vein appears to bifurcate. This unusual pattern of 

secondary vein behavior could simply represent a developmental abnormality (teratology), a distinct possibility 

considering the preservation of only one specimen. 

Alternatively, such variable behavior in secondary venation could reflect the low degree of vein organization that 

typifies many species of early angiosperms. 

Landonia calophylla cannot be placed within an 

extant family but most closely resembles Laurales of 

primitive to intermediate advancement (table 2; pl. 6, 

fig. 1; pl. 7; text figure 6). Among extant dicots, the 

combination of irregular secondary and higher order 

venation and laminar secretory cells is restricted to 

subclass Magnoliidae. Within Magnoliidae, the features 

of secondary and tertiary venation found in L. calophylla 

occur only in Laurales but never within a single extant 

family. Landonia resembles Amborellaceae, Austrobaileyaceae, and Monimiaceae in having an ovate to oblong 

shape, clustering of the basalmost 2-3 pairs of secondary 

veins, and predominantly isodiametric intercostal regions 

above the base of the lamina; within this group, Landonia 

most closely resembles Monimiaceae such as Ephippiandra in having sinuous margins to the intercostal 

regions. In contrast, Landonia resembles Gomortegaceae in having the following set of venational features: 

(1) excostal secondary loops that have a highly irregular 

shape, (2) widely spaced intercostal tertiary veins that 

have a weakly transverse to oblique orientation (compare 

the tertiary veins from the uppermost intercostal region 

of Landonia calophylla in pl. 6, fig. 3, and text figure 7 

with those of Gomortegakeule (Mol.) Baill. in pl. 6, fig. 1, 

and text figure 6), (3) the tendency for these intercostal 

tertiary veins to give rise to thinner lateral branches, 

usually on their admedial sides, and ( 4) admedially 

ramified excostal tertiary veins. This mixing of features 

that today are restricted to separate families is of phylogenetic significance, because it provides an intermediate 

condition between what is found in extant Monimiaceae 

and extant Gomortegaceae (table 2). Thus, Landonia 

calophylla provides paleobotanical evidence for the close 

relationship postulated between Monimiaceae and 

Gomortegaceae on the basis of comparative morphology 

(Takhtajan, 1980). 

20 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Table 2. Comparison of Landonia and related extant taxa 

Taxon Shape of Margins of 

intercostal intercostal 

regions regions 

Landonia--------- lsodiametric above Highly sinuous----

base of lamina. 

Austrobaileyaceae Isodiametric above Curved------------

base of lamina. 

Amborellaceae---- Isodiametric above Mostly straightbase of lamina. sided. 

Monimiaceae------ Isodiametric above Straight-sided 

base of lamina in to sinuous, most genera. depending on genus. 

Gomortegaceae---- Exmedially elongate Slightly sinuous--

Hernandiaceae---- Exmedially elongate Straight-sided----

in leaves that have at least several 

pairs of secondary 

veins. 

Pabiania new genus 

Diagnosis.-Lamina predominantly 3-lobed rarely 

2-lobed or unlobed; margin entire. Primary venation of 

lobed forms suprabasal palinactinodromous; lateral primary veins decurrent on midvein, at lower angle than 

superadjacent secondary veins. Basilaminar secondary 

veins strongly developed, at same angle as the lateral 

primary veins or (in unlobed forms) superadjacent pair 

of secondary veins. Sinus bracing accomplished by the 

lowest pair of secondary veins on the midvein, these 

running directly to the sinus and bifurcating at the 

laminar margin, with each branch of the bracing vein 

running subparallel to laminar margin and connecting 

with the secondary veins of the lobes. Tertiary venation 

irregularly branched; tertiary veins thin and oriented at 

right or low obtuse angles to primary veins. Quaternary 

venation non-orthogonal. Quinternary venation weak, 

irregular; quinternary veins highly branched and showing 

a strong tendency to ramify within the areoles. 

Guard cell pair elongate, elliptic to spindle shaped; 

lamellar cuticular thickenings present to absent, sometimes on the same leaf. Stomatal complex generally 

brachyparacytic, but with some leaves having rare laterocytic, hemiparacytic, and weakly cyclocytic to anomocytic 

stomata. Trichome bases (when present) consisting of an 

angular, heavily cutinized pore and associated cells that 

Margins of Intercostal Excostal 

excostal tertiary tertiary 

secondary loops venation venation 

Highly sinous----- Transverse to Admedially 

oblique, with ramified. 

thinner and usually 

admedially oriented 

lateral branches, 

thicker branches 

sometimes with a tendency to be 

admedially ramified near midvein. 

Curved------------ Reticulate and Reticulate. 

admedially oriented. 

Straight-sided Reticulate and Reticulate and 

to sinuous. admedially ramified admedially 

near midvein. ramified. 

Straight-sided Usually reticulate Reticulate to 

to moderately and admedially admedially 

sinuous, depending ramified near ramified. 

on genus. midvein. 

Highly sinuous---- Transverse to Admedially 

oblique, with widely ramified. 

spaced veins that 

produce admedially 

ramified lateral 

branches. 

Tending to be Transverse to Usually 

rounded, often oblique, usually admedially 

slightly reticulate, rarely ramified. 

sinuous. as in Gomortegaceae. 

are scarcely modified but show a strong tendency to be 

radially oriented. 

Type species.-Pabiania variloba Upchurch and 

Dilcher. 

Derivation of generic name.-In honor of Roger 

Pabian, and in recognition of his discovery of the Rose 

Creek locality and other contributions to Nebraska 

geology. 

Pabiania variloba new species 

Plate 8; plate 9, figures 1-3; plate 11, figures 1-7; 

text figures 8 and 9 

Acerites multiformis Lesquereux, Retallack and Dilcher, 1981, fig. 4. 

Diagnosis.-As for genus. 

Description.-Phyllotaxy opposite and decussate. 

Leaf commonly trilobate, rarely bilobate or unlobed; 

base ranging from acute to obtuse and tending towards 

cuneate, with the basalmost portion of the lamina decurrent on the petiole; margin entire. Trilobed leaves with 

their widest part above the middle of the lamina, L/W 

0.8-1.0; blade 2.5-5.7 em long by 2-5.5 em wide; medial 

lobes 0.7-2 em long, sometimes with the widest part 

above the base; lateral lobes 0.6-1.6 em long (measured 

from the sinus to lobe tip), oriented at acute angles to the 

medial lobe, with their apical sides oriented at broad 

Systematics 21 
Figure 8. Pabiania variloba new genus ·and 

species, 15713-3327, specimen shown on 

plate 8, figure 4, x 3. 

acute to right angles to the midvein; apex of lobes acute 

to rounded; petiole preserved in two isolated trilobed 

leaves, 3.5-4.2 em long, shorter in leaves preserved on a 

shoot, but this possibly resulting from fossilization of the 

leaves in an immature state. Unlobed leaves broad 

elliptic to obovate, L/W 1-2; blade 1.5-3 em long by 

1.7-4 em wide; apex rounded; petiole not preserved in 

any isolated unlobed leaves. Primary venation suprabasal 

palinactinodromous in 3-lobed leaves, pinnate in unlobed 

leaves; midvein moderate; lateral primary veins similar to 

midvein in thickness, at lower angle than superadjacent 

secondary veins and tending to be recurved, commonly 

decurrent on midvein, producing 1-3 festooned brochidodromous external branches. Secondary venation 

fundamentally festooned brochidodromous; secondary 

veins thin or moderate relative to primary veins, 3-6 pairs 

along midvein, with one pair of basilaminar secondary 

veins present in all leaves, alternate, moderate acute, 

straight to apically curved, looping tending to be 

festooned brochidodromous except near sinuses, where 

the secondary veins connect with a branch of the sinusbracing vein; angle of brochidodromous junction rightangled to obtuse; excostal secondary loops curving apically. Intersecondary veins absent. Tertiary venation 

unbranched to bordering on reticulate; tertiary veins thin 

relative to secondary veins, opposite to alternate, closely 

but somewhat irregularly spaced, originating at acute to 

right angles, bending at points of branching and at 

junctions with other tertiary veins, oriented at 90°-110° to 

primary veins. Quaternary venation intergrading with 

tertiary venation, generally unbranched; quaternary veins 

opposite to alternate, non-orthogonal, enclosing somewhat elongate, 4-sided regions. Quinternary venation 

highly irregular, both ramified and reticulate, arising 

both from thick lateral branches of the quaternary veins 

and from the sides of lower order veins; quinternary veins 

weak, curved, often producing a series of H-shaped 

branches that can suddenly change orientation. Areolation poorly developed, average areolar size minute. 

Marginal venation consisting of a thin fimbria! vein. 

Upper cuticle of medium thickness, with welldeveloped flanges; cell shape isodiametric to mixed, cells 

generally 4 to 5 sided, rarely 3 or 6 sided, 12-30 microns 

long by 6-22 microns wide, anticlinal wall contour 

commonly straight, more rarely curved; cells with sharp 

corners; external and internal sculpture smooth under 

light microscopy x 500. Trichome bases present on the 

upper cuticle of some specimens, consisting of a small, 

heavily cutinized pore and several associated cells; pore 

isodiametric to elongate, with straight to concave sides; 

associated cells tending to be radially oriented and 

underthrusting the outer rim of the pore. Two types of 

idioblasts observed on the upper cuticle; the first type of 

idioblast consisting of a single cell with the shape and 

cutinization of trichome bases, perhaps representing the 

basal cell of an abscissed trichome, common; the second 

type of idioblast similar to unmodified epidermal cells 

but with thin outer cuticle, adjacent cells with secondary 

divisions parallel to the anticlinal walls of the idioblast, 

found in only one specimen. 

Lower cuticle ranging from medium to thin, 

usually thinner than the upper cuticle and often adhering 

to it in preparations; flanges typically present but 

sometimes only visible with phase-contrast microscopy; 

cell shape and number of sides as on upper cuticle; cells 

12-38 microns long by 8-32 microns wide; anticlinal wall 

contour straight-curved, rarely undulate, when undulate 

with no more than one wavelength per cell side; external 

and internal sculpture smooth under light microscopy 

x 500. Guard cell pair usually elliptic, rarely rectangular 

or spindle-shaped, L/W usually 2-3, 15-30 microns long 

by 6-18 microns wide; stomatal poles flattened to 

truncate; lamellar cuticular thickenings present on the 

guard cells of many specimens, occurring on the outer 

walls and not extending the full length of stoma, not 

present in other specimens, but here with an elaborated 

cuticular flange adjacent to the subsidiary cells (this 

elaborated flange is similar to the lamellar cuticular 

thickenings in Pandemophyllum ). Subsidiary cell arrangement usually brachyparacytic, but with rare laterocytic, 

hemiparacytic, and weakly cyclocytic to anomocytic 

stomata present on some leaves; subsidiary cells often 

with curved tangential walls and showing a tendency to be 

radially compressed, in a few specimens with thinner 

outer cuticle either over the entire subsidiary cell or in a 

22 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Figure 9. Pabiania variloba new genus and species, 15713-4845, specimen shown on 

plate 9, figure 2. The circular regions on the leaf represent galls. A, General view of venation, 

x 3. 8, Closeup of sinus region (upper left corner of 9A) showing details of sinus bracing 

and higher order venation, x 7.5. 

narrow zone adjacent to the guard cells. Trichome bases 

present on many specimens, structure as for upper 

cuticle. Idioblasts present on one specimen, identical to 

the first type observed on the upper cuticle. Mesophyll 

secretory bodies present in most cuticular preparations, 

spherical, similar in diameter to the epidermal cells, 

interpreted as the remains of secretory cells. 

Number of specimens examined for foliar 

architecture.-> 100. 

Number of specimens examined for cuticular 

anatomy.-16. 

Holotype.-15713-3317, 3317'_ (part and 

counterpart). 

Paratypes.-15713-3316, 3318, 3320, 3320', 3327, 

3546,4845,4847,7801, 7801', 7838,7839,7840,7841. 

Derivation of epithet.-Latin, varius =variable, 

lobus= lobe, referring to the variable development of 

lobation. 

Discussion.-The name Pabiania is proposed for 

predominantly 3-lobed foliage of Cretaceous age that 

traditionally has been assigned to Lauraceae. Typically, 

foliage of the Pabiania-type has been assigned to the 

extant lauraceous genera Sassafras and Lindera, which 

have a similar shape and pattern of sinus bracing. 

However, analysis of higher order venation indicates that 

these generic assignments, as well as an assignment to 

extant Lauraceae, are incorrect. All extant Lauraceae are 

characterized by quaternary venation that has at least 

tendencies for orthogonal rooting, and the majority of 

genera possess reticulate quinternary venation that forms 

a fairly regular network of areoles. (For examples, see 

pl. 9, fig. 5 and pl. 10, fig. 1.) This suite of features is 

interpreted to be derived within Laurales, because it is 

absent from the more primitive families of the order, 

such as Amborellaceae, Trimeniaceae, Idiospermaceae, 

Atherospermataceae, and Gomortegaceae, and occurs 

only in relatively derived families, such as Lauraceae and 

Gyrocarpaceae. Pabiania, in contrast, possesses the 

generalized features of higher order venation that characterize most families of Laurales; namely, quaternary 

venation that originates at variable angles and quinternary venation that is highly ramified and forms an 

irregular system of areoles. Although the occurrence of 

primitive higher order venation in the fossils does not in 

itself preclude a close common ancestry with Lauraceae, 

primitive higher order venation does preclude an assignment to extant genera of Lauraceae such as Sassafras and 

Lindera. 

No previously described fossil taxon has a generic 

name that can validly be applied to the Rose Creek 

remains. Acerites Viviani, a name used for these same 

remains by Retallack and Dilcher (1981) and for similar 

Dakota remains by Lesquereux (1892), cannot be used 

because the type species, Acerites ficifolia (Viviani, 1833, 

p. 131, pl. 9, fig. 5), has a different pattern of primary 

venation and hence appears to belong to a different 

genus and family. Araliaephyllum Fontaine cannot be 

used because the type species, A. obtusilobum (Fontaine, 

1889, p. 317, pl. 163, fig. 14; pl. 164, fig. 3) is five-lobed, 

with basally palinactinodromous primary venation and a 

Systematics 23 
different pattern of sinus bracing. No other previously 

described fossil genus has a suite of venational features 

similar to that of the Rose Creek remains. 

Although Pabiania variloba was originally assigned 

to the species ''Acerites" multifonnis Lesquereux (Retallack and Dilcher, 1981 ), close examination of foliar 

architecture indicates that it represents a distinct, though 

similar, species. P. variloba differs from "A." multifonnis 

in having the combination of suprabasal palinactinodromous primary venation, sinus bracing accomplished by a 

vein that originates from the midvein and bifurcates at 

the sinus margin, and (in trilobed leaves) the absence of 

subsidiary lobes on the middle lobe. Pabiania variloba 

shows close similarities to additional species of trilobed 

leaves known from uppermost Albian and Cenomanian 

strata; however, most of these species lack preserved 

venation above the first or second order, making detailed 

comparisons difficult. In terms of size and shape, P. 

variloba most closely resembles "Sassafras" bradleyi 

Brown from the mid-Cretaceous (upper Albian to lower 

Cenomanian) Aspen Shale of Wyoming (Brown, 1933, 

pl. 2, fig. 5); however, the two taxa are probably not 

conspecific because the sinus-bracing vein in "S." bradleyi 

appears to bifurcate within the margin. Further, "S." 

bradleyi lacks preserved venation above the second order. 

Among angiosperms from the Dakota Formation, P. 

variloba most closely resembles "Lindera" venusta 

(Lesquereux, 1892, pl. 16, figs. 1, 2) in size and shape but 

differs in having suprabasal lateral primary veins and 

possibly somewhat different sinus bracing. Other taxa of 

Late Cretaceous angiosperm leaves showing strong 

similarities to P. variloba in shape and lower order 

venational features include certain specimens of 

"Sassafras" acutilobum Lesq. as illustrated l-; Newberry 

(1895, pl. 25, figs. 1-10; excluding pl. 26, figs. 2-6) and 

"Sassafras" progenitor Newberry (1895, especially pl. 27, 

fig. 3). However, P. variloba differs from S. acutilobum in 

having stronger basal lobes and from S. progenitor in 

having suprabasal lateral primary veins. 

Pabiania variloba also shows similarities to Albian 

species of angiosperm leaves invalidly assigned to Lauraceae, including "Sassafras" bilobatum Fontaine (1889, 

pl. 156, fig. 12; pl. 164, fig. 4) and "S." potomacensis 

Berry (1911a, pl. 94, fig. 1). Among these taxa, two 

specimens assigned to "Sassafras" potomacensis by 

Hickey and Doyle (1977, figs. 49-51) preserve features of 

higher order venation that indicate a close relationship 

with Pabiania. These two specimens not only resemble 

Pabiania variloba in size, shape, sinus bracing, and 

pattern of origin for external branches of the lateral 

primary veins, but they also resemble Pabiania in 

possessing tertiary and quaternary venation that is 

comparable in vein thickness and degree of organization. 

(Higher order venation is more reticulate and widely 

spaced in "S ." potomacensis.) These strong similarities in 

both lower and higher order venation between Pabiania 

variloba and Early Cretaceous remains assigned to 

"Sassafras" potomacensis indicate that Pabiania probably 

originated from a trilobed complex of Early Cretaceous 

Laurales. 

Among unlobed fossil angiosperm leaves, Pabiania 

shows strong similarities in foliar architecture and 

cuticular anatomy to the genus Cocculophyllum ( especially those species illustrated by Nemejc and Kvacek 

(1975) and Kvacek (1983) from the Upper Cretaceous of 

Czechoslovakia), implying a close relationship. Features 

shared by these two genera include decurrent and 

typically suprabasal lateral primary veins, closely spaced 

and irregularly branched tertiary veins, quaternary veins 

that originate at highly variable angles and are typically 

unbranched, elongate and sometimes spindle-shaped 

guard cells that have poorly developed lamellar 

thickenings, an arrangement of subsidiary cells that is 

predominantly brachyparacytic but has laterocytic and 

other stomatal types, and hair bases comprising an isodiametric polygonal pore with heavily cutininized anticlinal walls. These similarities also are shown by Pabiania 

and the latest Cretaceous species "Cinnamomum" linifolium Knowlton (1917, pl. 90, fig. 3), which was allied with 

the genus Cocculophyllum by Upchurch and Wolfe 

(1987a). The only consistent differences shown by Pabiania and Cocculophyllum are the strong tendency for 

lobation in Pabiania, a consistently higher L/W ratio in 

Cocculophyllum, and perhaps a more uniform arrangement of subsidiary cells in Pabiania. We interpret these 

differences as significant at the generic level by analogy to 

extant Lauraceae, where lobed leaves are restricted to 

certain genera. 

The modern affinities of Pabiania variloba clearly 

lie with the order Laurales (table 3; see pl. 7, pl. 9, figs. 4, 

5, and pl. 10 for illustrations of extant Laurales ). A 

relationship to either Magnoliidae or very primitive 

families of non-magnoliid dicots is indicated by low 

degree of organization in the venation, lamellar cuticular 

thickenings on the guard cells, and the presence of 

mesophyll secretory cells. Within this group, only Laurales possess the combination of suprabasal palinactinodromous primary venation with decurrent lateral 

primaries; basilaminar secondary veins; sinus bracing 

accomplished by a secondary vein that originates from 

the midvein and bifurcates at the laminar margin; highly 

ramified quinternary venation composed of thin and 

curving veins; brachyparactyic subsidiary cells; and trichome bases composed of an isodiametric, heavily cutinized, polygonal pore and scarcely modified base cells. 

Among non-magnoliid dicotyledons, certain Araliaceae, 

such as Gilbertia, have primary and secondary venation 

and sinus bracing similar to that of Pabiania, which could 

be taken to indicate that Pabiania represents Araliaceae. 

However, Araliaceae are readily distinguished from 

24 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Table 3. Comparison of Pabiania, Pandemophyllum, and related extant taxa 

Taxon Lobation Margin Lateral 

primary veins 

Basi laminar 

secondary 

venation 

Intercostal 

tertiary 

venation 

Quaternary 

venation 

Areolation Embedded 

guard 

cells? 

Subsidiary 

cell 

arrangement 

Pabiania---------- Present-- Entire-- Well developed, 

decurrent on 

midvein. 

Well developed-- Subparallel, Usually Poorly No-------- Paracytic. 

Pandemophyllum---- Absent--- Entire-- Absent--------- Weak pair 

of secondary 

veins near 

base of 

lamina. 

irregularly unbranched developed, 

branched and non- FEV' s 

close-spaced. orthogonal. highly branched. 

Subpar a ll e l , 

irregularly 

branched, 

moderately 

spaced. 

Unbranched Moderately Yes------- Paracyt i c. 

to reticulate developed, 

or ramified, FEV's 

at more not present 

regular angle. in all areoles. 

Atherospermataceae Absent--- Entire Absent--------- Absent·······--- Usually Usually 

reticulate, 

can be 

strongly 

ramified. 

Moderately 

to poorly 

developed, 

FEV's often 

highly 

branched. 

No-------- Paracytic or 

anomocyt i c, 

depending 

or with reticulate 

Monimioid can be 

teeth. strongly on genus. 

transverse. 

Gomortegaceae----- Absent--- Entire-- Absent--------- Absent---------- Weakly trans- Ramified-----

verse, widely 

Poorly 

developed 

FEV's highly 

branched. 

No-··----- Paracyt i c, 

with a few 

Gyrocarpaceae----- Absent--- Entire--

Hernandi acee------

Hortoni aceae------

Lauraceae---------

Present 

in one 

sp. of 

~-

Absent---

Present 

in some 

genera. 

Entire--

Entire--

Entire·· 

Well developed, 

originating 

from base 

of lamina. 

Present in some 

species, can be 

decurrent on 

midvein. 

Well developed, 

decurrent on 

midvein. 

Well developed 

in some genera, 

point of 

origin varies. 

Present---------

Weakly 

developed 

to absent. 

Well developed--

Well developed 

in some genera. 

Pabiania by their cuticular anatomy, especially by having 

well-developed outer stomatal ledges on the guard cells 

and a ring of weakly specialized subsidiary cells. Within 

Laurales, the families Amborellaceae, Austrobaileyaceae, and Monimiaceae can be excluded from consideration by their combination of pinnate venation, 

intercostal regions that are isodiametric above the base 

of the lamina, and tertiary venation that is strongly 

reticulate or ramified (table 2). Among the remaining 

extant families of Laurales (table 3), Pabiania shows 

a pattern of tertiary and quaternary venation most 

comparable to that of Idiospermaceae (pl. 7, fig. 8) 

and one species of Atherospermataceae (Siparuna 

decipiens-pl. 9, fig. 4) and a low level of areolar 

organization characteristic of all Laurales except Austrobaileyacee, Gyrocarpaceae, and Lauraceae. This implies 

a level of advancement in tertiary and higher order 

venation comparable to that of Idiospermaceae and 

Atherospermataceae. 

In terms of a possible cladistic relationship, Pabiania shows a probable common ancestry with Gyrocarpaceae, Hernandiaceae, Hortoniaceae, and Lauraceae. 

Evidence for this hypothesis is the presence of wellspaced, with 

admedially 

ramified lat· 

era l branches. 

Reticulate, 

oriented 

transverse 

to midvein. 

Reticulate, 

transverse 

to mi dvei n 

or secondary 

veins. 

Reticulate, 

transverse 

to mi dvei n. 

Reticulate to 

percurrent, 

strongly 

organized. 

Reticulate, 

tend i ng to be 

orthogonal. 

Reticulate to 

ramified. 

Reticulate 

and ramified, 

rooting + 

orthogonal 

Usually 

orthogna l 

reticulate, 

unbranched 

and ramified 

in 

Eus i deroxyl on 

Moderately 

developed, 

FEV' s 

branched. 

Poorly 

developed, 

FEV' s 

highly 

branched. 

Moderately 

developed, 

FEV's highly 

branched. 

Well developed 

in all genera, 

except 

Eusideroxylon, 

FEV' s branched 

to absent. 

No--------

l aterocyt i c 

to cyclocytic 

stomata. 

Anomocyt i c. 

No-------- Anomocytic. 

No-------- Anomocytic. 

Yes------- Paracyt i c. 

developed lateral primary veins within at least some 

species of each taxon. Lateral primary veins are probably 

derived within Laurales because they are absent from 

more primitive families in the order. The predominantly 

trilobed condition in Pabiania and the distinctive pattern 

of sinus bracing invites comparison with Lauraceae, as 

does the shape of the guard cells and the predominantly 

brachyparacytic arrangement of subsidiary cells. However, Pabiania appears to be more primitive than extant 

Lauraceae in having (1) the irregular areolation with 

highly branched freely ending veinlets characteristic of 

most primitive Laurales, (2) guard cells that show little 

evidence of being embedded in the subsidiary cells (a 

feature that, within Laurales, only occurs in Lauraceae ), 

and (3) subsidiary cell arrangement that is more variable 

than that of Lauraceae. (See pl. 11, fig. 8, and pl. 17, 

figs. 5-7 for illustrations of extant Lauraceae.) Further, 

lobation is a character that typically varies on an individual plant in Lauraceae as well as between individual 

species, which indicates the possibility of parallel 

evolution, and most Lauraceae have alternate, rather 

than opposite and decussate, phyllotaxy. Thus, Pabiania 

shows a close relationship with intermediate to derived 

Systematics 25 
families of Laurales, with the closest relationship possibly 

being to Lauraceae. 

Pandemophyllum new genus 

Diagnosis.-Leaf simple; demarcation between 

petiole and blade indistinct; margin entire and with 

structural reinforcement. Primary venation pinnate. 

Secondary venation festooned brochidodromous but 

forming flattened brochidodromous arches in at least the 

apical quarter of the lamina; strong basilaminar secondary veins absent but with a thin pair of secondary 

veins present near the base of the lamina. Intersecondary 

veins present in some intercostal regions, branching to 

form tertiary veins. Tertiary venation unbranched to 

reticulate, often with a ramified component, irregularly 

transverse; tertiary veins irregularly spaced, enclosing 

regions no more than 2-3 times as long as wide. Quaternary venation unbranched to reticulate and ramified; 

quaternary veins non-orthogonally rooted, often irregularly transverse to the tertiary veins, irregularly spaced, 

tending to be admedially branched. 

Cuticle of medium thickness, easy to prepare, 

flanges well developed. Guard cells typically spindle 

shaped, with well-developed lamellar thickenings along 

the boundary with the inner pair of subsidiary cells, 

strong lamellar thickenings developed over the inner pair 

of subsidiary cells in some species, lamellar cuticular 

thickenings often appearing to "float" in the stomatal 

complex under light microscopy. Stomatal complex brachyparacytic to amphibrachyparacytic. Trichome bases, 

when present, consisting of an angular to rounded pore 

with a heavily cutinized margin and several adjacent cells 

that often are radially oriented. 

Type species.-Pandemophyllum kvacekii. 

Derivation of name.-Greek, pandemos =common, phyllos =leaf, referring to the widespread occurrence of this leaf type during the Late Cretaceous. 

Pandemophyllum kvacekii new species 

Plate 12; plate 13, figures 1, 2; plate 15; text figure 10 

Diagnosis.-Lamina narrow elliptic to narrow subrhombic, L/W 2.8-3.6, apex acute to attenuate with a 

rounded tip. Secondary veins oriented approximately 45° 

to primary vein, curving sharply near the margin just 

before forming loops, flattened brochidodromous arches 

present only near the tip of the leaf. Tertiary veins 

moderate relative to the secondary veins, unbranched to 

reticulate, ranging from roughly transverse to the 

secondary veins to nearly parallel to the primary vein, 

Figure 10. Pandemophyllum kvacekii new 

genus and species, 15713-4847, specimen 

shown on plate 13, figures 1 and 2. Note the 

separate strands in the midvein and the 

reticulate higher order venation, x 15. 

sometimes on the same leaf. Quaternary venation 

unbranched to reticulate, similar to tertiary venation in 

course and branching, generally enclosing elongate 

regions oriented transverse to the tertiary veins. 

Description.-Lamina elliptic to rhomboidal, 

L/W 2.8-3.6; lamina 6-16 em long by 2.1-4.5 em wide 

(maximum length estimated); apex acute and with a 

rounded tip; base acute to cuneate; boundary between 

petiole and blade not well defined, petiole 1.2 em long 

(only one petiole completely preserv~d); margin entire, 

in many specimens somewhat darkened (structurally 

reinforced). Primary venation pinnate; primary vein stout 

to massive, sometimes curved near the base of the 

lamina, appearing to be composed of separate vascular 

strands. Secondary venation festooned brochidodromous, brochidodromous loops flattened only in the apical fourth of the lamina; secondary veins thin relative to 

the primary vein, ranging from 6 to over 10 pairs per leaf, 

predominantly opposite to subopposite, predominantly 

moderate (rarely narrow) acute; course more or less 

straight until forming loops, curving strongly just before 

forming loops near margin; intercostal regions always 

exmedially elongate but decreasing in length apically; 

brochidodromous junction formed by two veins of nearly 

equal thickness, the superadjacent vein deflected apically 

only where the costal loops are flattened, angle of brochidodromous junction broad acute to obtuse; one well26 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
developed series of excostal secondary loops present, 

these apically oriented. Intersecondary veins rare, 

branching to form tertiary veins. Tertiary venation 

unbranched to reticulate; tertiary veins moderate relative 

to secondary veins, ranging from acute to obtuse on the 

exmedial side of the secondary veins and acute to rightangled on the admedial side, irregularly spaced, course 

somewhat irregular, orientation roughly transverse to 

nearly parallel to primary vein. Quaternary venation 

unbranched to reticulate, similar to the tertiary venation 

in behavior; quaternary veins thin or moderate relative to 

the tertiary veins, non-orthogonally rooted, tending to 

enclose elongate regions roughly transverse to tertiary 

veins. Quinternary venation poorly preserved on most 

specimens, irregularly reticulate; quinternary veins often 

curved. Areolation moderately developed, areoles 

typically quadrangular, isodiametric to elongate, minute, 

0.1-0.2 mm in diameter, with straight or curved sides, 

freely ending veinlets possibly present adjacent to tertiary 

and quaternary veins, but difficult to distinguish from 

preservational artifacts. Marginal venation obscure. 

Upper cuticle with well-developed flanges; cell 

shape mixed; cells 4-6 sided, 10-38 microns long by 

10-22 microns wide; anticlinal wall contour a mixture of 

straight and curved; external and internal sculpture 

smooth under light microscopy x 500; trichome bases 

present, each comprising an isodiametric, angular pore 

with thickened walls and several base cells that are often 

radially arranged, pore usually less than 10 microns in 

diameter. 

Lower cuticle somewhat thinner than upper cuticle 

but with well-developed flanges; cell shape mixed; cells 

4-6 sided, 12-46 microns long by 5-20 microns wide; 

anticlinal wall contour a mixture of straight and curved; 

surface sculpture and internal sculpture smooth under 

light microscopy x 500. Guard cells elliptic to spindleshaped; lamellar cuticular thickenings strongly developed 

at the junction with subsidiary cells, sometimes well 

developed over the inner pair of subsidiary cells, with 

intermediate conditions present; lamellar cuticular 

thickenings not extending the full length of the guard cell, 

under light microscopy often appearing to "float" in the 

stomatal complex; subsidiary cell arrangement brachyparacytic to more commonly amphibrachyparactyic, 

usually with two to three pairs of subsidiary cells but with 

up to four pairs observed; inner pair of subsidiary cells 

typically elongate parallel to the guard cells, up to 12 

microns wide but usually much narrower; outer pairs of 

subsidiary cells less modified than inner pair, typically 

with curved tangential walls and often with thinner 

cuticle than unspecialized cells. Cells adjacent to stomatal complex often radially compressed (that is, 

elongate parallel, rather than perpendicular, to the stomatal complex), forming a weak ring of encircling cells. 

Trichome bases present, similar in structure to those of 

the upper cuticle, pore usually < 10 microns in diameter. 

Idioblasts present, possibly related to trichome bases 

ontogenetically, each consisting of a small, angular cell 

with heavily cutinized walls. Spherical secretory bodies 

present in a few cuticular preparations, typically several 

times the diameter of the epidermal cells, interpreted as 

the remains of mesophyll secretory cells. 

Number of specimens examined for foliar 

architecture.-70. 

Number of specimens examined for cuticular 

anatomy.-13. 

Holotype.-15713-7877. 

Paratypes.-15713-3323b, 3667b, 3671b, 3671c, 

3672,4716,4797,4799,4800a, 7851,7877,8300. 

Derivation of epithet.-In honor of Dr. Zlatko 

Kvacek, and in recognition of his studies of the cuticular 

anatomy of Late Cretaceous angiosperm leaves. 

Discussion.-Foliage of Pandemophyllum, along 

with similar leaf types known only as poorly preserved 

impressions, appears to be a common and diverse element in Late Cretaceous leaf floras from North America 

and Europe (see Nemejc and Kvacek, 1975; Kvacek, 

1983) and comprises the "protolaurels" of Wolfe and 

Upchurch (1987a). Traditionally, leaf impressions with 

the generalized lower order venation characteristic of 

Pandemophyllum have been assigned to a wide variety of 

extant dicotyledonous families belonging to Magnoliidae 

and other subclasses, presumably because of highly 

generalized foliar architecture. Some forms have been 

assigned to Lauraceae, including the extant genus Laurus 

(Laurus plutonia Heer as illustrated in Lesquereux, 1892, 

pl. 13, figs. 5, 6; pl. 22, fig. 5) as well as the form genera 

Laurophyllum Goeppert and Daphnophyllum Heer; 

however, the degree of differentiation between petiole 

and blade and pattern of higher order venation in Pandemophyllum indicates that an assignment to Lauraceae 

may be incorrect. Other forms have been placed within 

Magnoliaceae ("Magnolia" pseudo-acuminata Lesquereux, 1892, pl. 24, fig. 2) and a variety of non-magnoliid 

families such as Salicaceae ("Salix" deleta Lesquereux, 

1892, pl. 3, fig. 8), Aquifoliaceae ("flex" scudderi Lesquereux, 1892, pl. 58, fig. 2), Ebenaceae ("Diospyros" 

pseudoanceps Lesquereux, 1892, pl. 22, fig. 1 ), Moraceae 

("Ficus" inaequalis Lesquereux, 1892, pl. 49, figs. 6-8; 

pl. 50, figs. 3, 6), Ericaceae ("Andromeda" paralatorii 

Heer sensu Lesquereux, 1892, pl. 19, fig. 1; pl. 52, fig. 6) 

and Leguminosae (Phaseolites fonnus Lesquereux, 1892, 

pl. 55, figs. 5, 6, 12). None of these assignments of 

Pandemophyllum-like foliage to extant genera and 

families can be considered valid, because the suite of 

venational and cuticular features present in Pandemophyllum is not known from these modern relatives, 

Systematics 27 
and most previously described fossil species lack 

preserved venation above the third order, which is 

needed to identify leaves with such generalized foliar 

architecture. 

No previously described fossil taxon has a generic 

name that can be applied to the Rose Creek foliage. 

Commonly, the names Laurophyllum Goeppert, Litsaeophyllum Deane, Daphnogene Unger, and Daphnophyllum 

Heer have been used for Cretaceous leaves of the 

Pandemophyllum-type; however, the use of these four 

names appears to be invalid. Laurophyllum Goeppert is 

an orthographic variant of the extant genus Laurophyllus 

Thunb. (Wolfe, 1977). Litsaeophyllum Deane cannot be 

used because the type species, L. wingellense (Deane, 

1902, p. 64; pl. 17, fig. 4), has well-developed lateral 

primary veins, which are restricted to only some genera 

of Lauraceae. Daphnogene Unger could possibly be used 

because the type species, D. cinnamomeifolia (Brongiart) 

Unger (1845, p. 227), is pinnately veined. However, 

illustrations of the type species imply that only two orders 

of venation and no cuticle are preserved, which indicates 

that a separate taxon could be represented, especially 

considering the Tertiary age. Daphnophyllum Heer is an 

orthographic variant of the extant genus Daphniphyllum 

Blume because both names are based on the same Greek 

roots. 

Other generic names used for foliage of the Pandemophyllum type show similar problems. For example, 

Proteophyllum has been used for certain species with 

lower order venation and cuticular anatomy similar to 

that of Pandemophyllum (Proteophyllum laminarium 

Velenovsky as illustrated in Nemejc and Kvacek (1975; 

p. 40, pl. 6, figs. 1, 4, 6; pl. 7, figs. 1, 2, 4, 6; pl. 19, 

figs. 1-6)); however, Proteophyllum cannot be used 

because the type species, P. bipinnatum Friedrich (1883, 

p. 335; pl. 28, figs. 1, 2), is bipinnately compound, and 

hence belongs to a totally different subclass (Hickey and 

Wolfe, 1975). Certain species assigned to Myrtophyllum 

strongly resemble Pandemophyllum in cuticular anatomy 

(Kvacek, 1983) and higher order venation (unpublished 

observations), which implies a close relationship. However, all species assigned to Myriophyllum possesses a 

distinct intramarginal vein that runs nearly the full length 

of the lamina, a distinction we think is significant at the 

generic level. 

Among previously described species of fossil 

leaves, Pandemophyllum kvacekii shows strong similarities to Daphnophyllum crassineJVe Heer (1869, pl. 7, 

fig. 2; pl. 11, fig. 5), reported from the Cenomanian of 

Czechoslovakia, in size, shape, and features of lower 

order venation. However, we hesitate to assign our fossils 

to this species because ( 1) no venation above second 

order was illustrated by Heer, and (2) the stomata of 

Czechoslovakian specimens assigned to this species by 

Kvacek (1983) differ from those in our specimens by 

showing the consistent development of lamellar cuticular 

thickenings on the inner pair of subsidiary cells and by 

possessing consistently thin cuticle over the outer pair of 

subsidiary cells. Organically preserved leaves assigned by 

Tanai (1979) to the species Laurophyllum kujianum 

differ from P. kvacekii in having stronger, more curved 

secondary veins, a better defined petiole, and possibly 

well-developed lamellar cuticular thickenings on the 

inner pair of subsidiary cells; this last character is difficult 

to interpret from the published photographs. Numerous 

other species of fossil leaves resemble P. kvacekii, but all 

differ in size and shape or lack enough preserved venation to indicate conspecificity. 

Among extant angiosperms, the combination of 

simple, pinnate organization, lamellar cuticular thickenings on the guard cells, paracytic subsidiary cells, and 

the presence of spherical mesophyll secretory cells is 

restricted to Magnoliidae. Within Magnoliidae, the combination of basilaminar secondary veins and trichome 

bases consisting of a small, isodiametric, polygonal pore 

with scarcely modified adjacent cells is restricted to 

Laurales. Within Laurales, Pandemophyllum most 

closely resembles Lauraceae and Atherospermataceae in 

foliar architecture and stomatal structure (table 3). 

Among these two families, Pandemophyllum more 

closely resembles Lauraceae in having an entire margin 

and a combination of two postulated derived features 

restricted to the family: (1) moderately developed areolation, and (2) guard cells that have strong cuticular 

lamellae developed along their junction with the inner 

pair of paracytic subsidiary cells (see pl. 17, figs. 5-7 for 

extant Lauraceae ). The stomatal structure found in Pandemophyllum could be taken as evidence for affinities 

with Myristicaceae, because extant Myristicaceae possess 

guard cells with strong lamellar cuticular thickenings 

along the junction with paracytic subsidiary cells; 

however, Myristicaceae also possess trichome bases that 

are distinct from those of Laurales (pl. 17, figs. 8, 9) but 

similar to those of many Magnoliales. Pandemophyllum 

closely resembles the lauraceous genus Eusidereroxylon 

(pl. 10, fig. 6) in having festooned brochidodromous 

secondary venation where the brochidodromous arches 

are flattened in the apical quarter of the lamina, a pair of 

weakly developed secondary veins near the base of the 

lamina, and a comparable (although slightly less regular) 

pattern of tertiary and quaternary venation. However, 

Pandemophyllum may be more primitive than any extant 

Lauraceae in having a less well differentiated petiole and 

blade and in having less rigidly organized tertiary venation and areolation than most Lauraceae. Determination 

of whether Pandemophyllum represents an extinct genus 

of Lauraceae or a closely related extinct family awaits 

discovery of its reproductive organs and future cladistic 

analysis of extant and fossil Laurales. 

28 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Pandemophyllum attenuatum new species 

Plate 13, figures 3-5; plate 16, figures 1-6; text figure 11 

Diagnosis.-Lamina lanceolate; apex longattenuate. Secondary veins originating at about 45°, 

commonly curved for their entire length in the basal half 

of the lamina; flattened brochidodromous arches present 

in the apical half of lamina; intercostal regions exmedially 

elongate basally, becoming predominantly isodiametric 

and with apical attenuation in the apical half of lamina. 

Tertiary venation predominantly reticulate; tertiary veins 

moderate relative to the secondary veins. 

Description.-Lamina lanceolate, L/W 5-8 ( estimated); lamina 12-16 em long (estimated) by 2-2.3 em 

wide; apex strongly attenuate; base probably acute (only 

partial base observed); margin entire, with mechanical 

reinforcement. Primary venation pinnate; primary vein 

moderate. Secondary venation festooned brochidodromous, with flattened brochidodromous arches in the 

apical half of the lamina; secondary veins moderate 

relative to primary vein, > 6 pairs, alternate to subopposite, with somewhat irregular spacing, originating at 

about 45°, slightly deflected where they give rise to 

tertiary veins, curving over most of their length in the 

basal half of the lamina; intercostal regions in the basal 

half of the lamina exmedially elongate, intercostal 

regions in the apical half of the lamina isodiametric and 

with an apical prolongation near their exmedial sides; 

brochidodromous junction formed by two veins of equal 

thickness, the superadjacent secondary vein deflected 

apically only in the apical half of the lamina; angle of 

brochidodromous junction obtuse in the apical half of the 

leaf; one well-developed series of excostal secondary 

loops present, these apically oriented. Intersecondary 

veins present in some intercostal regions, branching to 

Figure 11. Pandemophyllum attenuatum 

new species, 15713-8305, specimen shown 

on plate 13, figure 5, illustrating details of the 

apex, x3. 

form tertiary veins. Tertiary venation predominantly 

reticulate; tertiary veins moderate relative to secondary 

veins, angle of origin variable, irregularly spaced, course 

somewhat irregular, tending to be oriented nearly 

parallel to the midrib. Quaternary venation poorly preserved, unbranched to reticulate, similar to the tertiary 

venation in behavior. Higher order and marginal venation obscure. 

Upper cuticle of medium thickness, with welldeveloped cuticular flanges; flanges 2-3 microns wide; 

cell shape mixed; cells 4-5 sided, 18-40 microns long by 

9-18 microns wide, tending to occur in clusters or linear 

groups, secondary divisions common; anticlinal wall 

contour tending towards curved; external and internal 

sculpture smooth under light microscopy x 500. Veinal 

areas consisting of rows of cells, these grouped into linear 

arrays of cells separated by thin cuticular flanges; linear 

arrays of cells following an undulatory path. Trichome 

bases present, each consisting of a small, concave-sided 

pore and several adjacent cells that tend to be radially 

oriented; pore heavily cutinized, possibly occluded. 

Lower cuticle of medium thickness, somewhat 

thinner than upper cuticle, with well-developed flanges; 

flanges approximately 2 microns wide; cell shape mixed; 

cells 4-6 sided, 12-36 microns long by 10--22 microns 

wide; anticlinal wall contour ranging from straight to 

curved; external and internal sculpture smooth under 

light microscopy x 500. Veinal areas consisting of rows 

of cells, these often undulating over smaller veins, 

undulations difficult to see for cells beneath the larger 

veins. Guard cells spindle-shaped, 22-30 microns long by 

3-10 microns wide, with well-developed lamellar cuticular thickenings along border with inner pair of subsidiary cells; subsidiary cell arrangement ranging from 

brachyparacytic to amphibrachyparactyic; the inner pair 

of subsidiary cells sometimes with well-developed lamellar cuticular thickenings, 2-10 microns wide; the unthickened subsidiary cells with cuticle of the same thickness as 

unspecialized cells. Trichome bases present, consisting of 

an isodiametric pore and several scarcely modified 

adjacent cells that tend to be radially oriented; pore 

ranging from angular to circular, up to 10 microns in 

diameter, heavily cutinized at the outer margin of hair; 

adjacent cells can be radially elongate. 

Number of specimens examined for foliar 

architecture.-7. 

Number of specimens examined for cuticular 

anatomy.-2. 

Holotype.-15113-1845. 

Paratypes.-15113-4698a, 4698b, 8305. 

Derivation of epithet.-Latin, attenuatus =drawn 

out, referring to the apex. 

Discussion.-Pandemophyllum attenuatum is distinguished from P. kvacekii by its lanceolate shape, 

attenuate apex, and different pattern of variation in the 

Systematics 29 
shape of the intercostal regions. Among previously 

described species of fossil angiosperm leaves, P. attenuatum most closely resembles "Salix" de/eta Lesquereux 

(1892, pl. 3, fig. 8; see pl. 14, fig. 2 of the present report) 

in having an ovate shape, attenuate apex, and similar 

tertiary and quaternary venation but differs in having 

more apically prolonged intercostal regions in the apical 

half of the lamina and in having predominantly reticulate, 

rather than predominantly unbranched, tertiary and 

quaternary venation. P. attenuatum also closely 

resembles Proteoides daphnogenoides Heer (pl. 14, fig. 4 

of the present report). However, the absence of 

preserved venation above the first order in type material 

of Proteoides daphnogenoides makes demonstration of 

conspecificity impossible; further, the genus Proteoides 

originally was proposed for leaves with poor preservation 

(Heer, in Capellini and Heer, 1866, p. 17). P. attenuatum 

also resembles "Inga" cretacea from the Dakota 

Formation of Kansas (Lesquereux, 1892, pl. 55, fig. 11; 

see pl. 14, fig. 1 of the present report) but differs in 

having well-developed intersecondary veins. 

Pandemophyllum sp. 

Plate 14, figures 5-6; plate 16, figures 7-9; plate 17, figures 1-3 

Description.-Fragment of one leaf preserved; 

lamina apparently very narrow elliptic and bordering on 

oblong; L/W well over 2, length well over 2.6 em, 

estimated width 1.5 em; apex and base missing; margin 

entire, with mechanical reinforcement. Primary venation 

pinnate; primary vein stout. Secondary venation festooned brochidodromous; secondary veins moderate 

relative to the primary vein, at least 6 pairs, alternate, 

with somewhat irregular spacing, originating at somewhat irregular angles that are always narrow acute (less 

than 45°), slightly deflected where they give rise to 

tertiary veins, curving apically when more than halfway to 

the margin; secondary veins looping near the margin, 

with both secondary veins of equal thickness at their 

junction and the superadjacent secondary vein deflected 

apically; angle of the junction (when preserved) obtuse; 

brochidodromous loops tending to be flattened. Excostal 

secondary veins slightly thinner than their source veins, 

forming somewhat irregularly proportioned loops that 

are elongate parallel to the margin. Intercostal tertiary 

venation tending towards unbranched; tertiary veins thick 

relative to the secondary veins and poorly differentiated 

from the quaternary veins, irregularly spaced, originating 

at an obtuse angle on the exmedial side of the secondary 

veins and at an acute angle on the admedial side of the 

secondary veins, oriented roughly parallel to the primary 

vein. Quaternary venation arising from thick lateral 

branches of the tertiary veins, non-orthogonal; quaternary veins highly branched, the branching tending to be 

admedially oriented; some quaternary veins ramifying 

into quinternary veins. Quinternary venation obscure. 

Marginal venation probably looped, obscured by the 

remains of the mechanical tissue. 

Upper cuticle medium, with well-developed 

flanges; flanges 2 microns wide; cell shape mixed; cells 

generally 4-6 sided, 12-24 microns long by 6-22 microns 

wide; anticlinal wall contour straight to curved. Veinal 

areas consisting of rows of cells; scattered stomata 

present adjacent to one observed veinal area. One trichome base observed, similar in construction to the 

trichome bases of other species. 

Lower cuticle medium, with well-developed 

flanges; flanges 1-2 microns wide; cell shape mixed; cells 

4-6 (rarely 3 or 7) sided, 18-40 microns long by 8-

26 microns wide; anticlinal wall contour straight to 

curved. Veinal areas poorly developed on cuticle, cells 

tending to be in longitudinal files over primary vein, cells 

tending to be isodiametric, files of cells weakly undulate. 

Guard cell pair spindle-shaped, 20-34 microns long by 

8-12 microns wide; stomatal poles truncate; guard cells 

with well-developed lamellar cuticular thickenings 

adjacent to inner pair of subsidiary cells; inner pair of 

subsidiary cells also with well-developed lamellar 

cuticular thickenings; subsidiary cell arrangement 

amphibrachyparacytic; inner pair of subsidiary cells 2-

6 microns wide; outer pair of subsidiary cells broader, 

with curved tangential walls, tending to be radially 

compressed, outer cuticle always thinner than that of 

unspecialized cells. Trichome bases and idioblasts not 

observed. 

Number of specimens examined for foliar 

architecture and cuticular anatomy.-1. 

Specimen.-15113-4821, 4827' (part and counterpart). 

Discussion.-Pandemophyllum sp. clearly represents a distinct species of Pandemophyllum, but the 

fragmentary preservation of the one known specimen 

precludes formal diagnosis. Pandemophyllum sp. is 

readily distinguished from other species of Pandemophyllum by (1) its nearly oblong shape, (2) brochidodromous 

loops that are more flattened in the middle portion of the 

lamina, (3) thick tertiary veins, ( 4) quaternary veins that 

tend to be admedially ramified, and (5) stomatal complexes in which the inner pair of subsidiary cells always 

has strongly developed lamellar cuticular thickenings and 

the outer pair of subsidiary cells always has thinner outer 

cuticle than adjacent unspecialized cells. 

cf. Order ILLICIALES 

Longstretbia new genus 

Diagnosis.-Lamina very narrow elliptic to oblong; 

petiolar region poorly differentiated from the lamina; 

margin ranging from entire to coarsely toothed. Primary 

30 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
venation pinnate. Secondary venation ranging from brochidodromous, with strongly flattened brochidodromous 

loops, to pinnate with an intramarginal vein; secondary 

veins numerous, decurrent, irregular in course and 

spacing. Intersecondary veins present, branching into 

tertiary veins. Tertiary venation irregularly reticulate, 

enclosing areas of variable shape. Higher order venation 

not present or poorly developed. 

Cuticle with well-developed flanges. Guard cell 

pair broad-elliptic to circular, over 30 microns long; 

T -pieces present at the stomatal poles; each guard cell 

with a C-shaped lamellar cuticular thickening. Subsidiary 

cell arrangement predominantly laterocytic, sometimes 

also with polar subsidiary cells. Epidermal secretory cells 

present, each consisting of an isodiametric, polygonal cell 

surrounded by larger but several scarcely modified cells. 

Type species.-Longstrethia varidentata. 

Derivation of name.-In honor of Karl Longstreth, 

and in recognition of his assistance to our research on 

early angiosperms. 

Longstretbla varldentata new species 

Plate 18; plate 19; plate 20, figure 1; text figure 12 

Diagnosis.-As for genus. 

Description.-Lamina linear, L/W over 6 to at least 

11; lamina 6-15 em long by 1-2 em wide; apex acute to 

abruptly rounded; base very narrow acute to cuneate; 

petiolar region poorly differentiated from the lamina and 

with a decurrent wing of laminar tissue; margin ranging 

from entire to having widely spaced teeth; teeth nonglandular, < 1 mm to 2 mm tall by 2 to 9 mm wide, 

variable in shape but tending towards straight-straight 

(B-2) or convex-convex (A-1 ), often strongly asymmetrical; angle formed by sides of teeth ranging from 

acute to obtuse; apex of tooth rounded. Primary venation 

pinnate; primary vein massive. Secondary venation 

ranging from brochidodromous with strongly flattened 

brochidodromous arches to pinnate with an intramarginal vein; secondary veins thin relative to primary vein, 

numerous, opposite to alternate, irregularly spaced, 

decurrent, narrow acute; course of secondary veins 

irregular and often sinuous, sometimes recurved just 

below junction with intramarginal vein; angle of brochidodromous junction obtuse. Intersecondary veins present, branching into tertiary veins. Intercostal tertiary 

venation very irregular, reticulate; tertiary veins nearly as 

thick as the secondary veins, originating at highly variable 

but commonly acute angles on both sides of the 

secondary veins, irregularly but widely spaced, often 

curved. Ultimate venation possibly of fourth order, 

poorly differentiated from tertiary venation. Areo!.;-tion 

moderately developed but of highly irregular shape, 

Figure 12. Longstrethia varidentata, new 

genus and species, 15713-4961 b, specimen 

shown on plate 18, figure 4. A, Central region 

of leaf, x 3. 8, Details of middle tooth, left 

margin, x 7.5. Note the absence of glandularity to the tooth. 

freely ending veinlets present in a few areoles, 

unbranched. Tooth venation consisting of a medial vein 

Systematics 31 
that is sometimes associated with much thinner unmodified veins; teeth not conforming to any of the types 

recognized by Hickey and Wolfe (1975). 

Upper cuticle thick, with well-developed flanges; 

cell shape mixed; cells 4-6 (rarely 5-7) sided, 30-

90 microns long by 20-55 microns wide; anticlinal wall 

contour straight to curved; external and internal 

sculpture smooth under light microscopy x 500. Veinal 

areas consisting of cells in rows. One idioblast observed, 

consisting of a small, isodiametric cell with straight to 

concave sides, underthrust by unmodified adjacent cells; 

idioblast with thicker cuticle than the adjacent cells, 

possibly representing the basal cell of an abscissed hair. 

Lower cuticle thick, with well-developed cuticular 

flanges; cell shape mixed; cells mostly 4-6 sided, 20-

72 microns long by 16-45 microns wide; maximum cell 

length and width on an individual cuticle usually no more 

than twice the minimum length and width; anticlinal wall 

contour usually straight to curved, rarely curved to 

undulate, when undulate with no more than 1 Y2 wavelengths per cell side; external and internal sculpture 

smooth under light microscopy x 500. Epidermal secretory cells present; each secretory cell isodiametric, 

straight-sided, and usually smaller than the adjacent cells, 

sometimes with attached resinous remains; adjacent cells 

ranging from radially oriented to radially elongate. One 

idioblast observed, similar to that of the upper cuticle but 

showing no strong cutinization. Guard cell pairs circular 

to broadly elliptic, with regions of cuticle on the outer 

walls that are significantly thinner than the outer cuticle 

of unspecialized cells, 38-60 microns long by 32-

57 microns wide; stomatal poles nearly always rounded, 

rarely slightly retuse; striations present on the stomata of 

a few specimens, concentric to the stomatal pore; lamellar cuticular thickenings well developed, those on the 

outer walls of the guard cells forming a ring concentric to 

the stomatal pore, those of the inner walls of the guard 

cells tending to be straight; T -pieces present on nearly 

every pair of guard cells, weakly to moderately developed; the upright present in all cases and sometimes 

flared towards the stomatal pores, up to several microns 

wide; crossbar present in some stomata, weaker than 

upright; subsidiary cell arrangement predominantly laterocytic, but with some stomata cyclocytic or intermediate between laterocytic and cyclocytic; number of 

lateral subsidiary cells predominantly 4-6, rarely 2 or 3. 

Mesophyll secretory bodies present in a few cuticular 

preparations, spherical, somewhat smaller in diameter 

than the epidermal cells, interpreted as the remains of oil 

cells. 

Number of specimens examined for foliar 

architecture.-98. 

Number of specimens examined for cuticular 

anatomy.-11. 

Holotype .-15713-4962. 

Paratypes.-15113-3668a, 3684b, 3691a, 3693a, 

4715, 4893, 4893', 4904, 4918, 4961a, 4961b, 4961c, 

7806, 8301. 

Derivation of name.-Latin, varius =variable, 

dentatus =toothed, referring to the variable development 

of teeth on the lamina. 

Discussion.-Traditionally, foliage of the Longstrethia type has been assigned to the genera Eucalyptus 

and Myrtophyllum (entire-margined forms) and Proteophyllum and Celastrophyllum (toothed forms). However, 

Longstrethia cannot be assigned to Myrtophyllum because 

its tertiary venation differs from that of the type species, 

M. geinitzii (irregularly reticulate rather than transversely 

oriented), and its stomatal structure differs significantly 

from that of M. angustifolium, a probable congener of M. 

geinitzii. (See Kvacek, 1983.) Longstrethia cannot be 

assigned to Proteophyllum because the type species of 

Proteophyllum is bipinnately compound (Friedrich, 

1883), and an assignment to Celastrophyllum is invalid 

because the type species of Celastrophyllum is entiremargined and has a distinct petiole (Goeppert, 1854). 

Finally, Longstrethia possesses a combination of features 

that invalidates an assignment to Eucalyptus and other 

extant Myrtales. These features include a decurrent wing 

of laminar tissue on the petiole, irregular intercostal 

venation with no preferred orientation, and lamellar 

cuticular thickenings on the guard cells, rather than outer 

stomatal ledges. 

Longstrethia shows some similarities with two 

additional genera of fossil angiosperm leaves but is 

distinct with respect to foliar features that typically 

circumscribe genera of extant angiosperms. Longstrethia 

resembles Rogersia Fontaine (1889) from the Lower 

Cretaceous Potomac Group of Virginia in having small 

size, a narrow elongate shape, and highly irregular 

tertiary venation, but it differs in having teeth in some 

specimens and in having an intramarginal vein. Longstrethia also resembles Eucalyptophyllum Fontaine 

(1889) from the Potomac Group in having an elongate 

shape and an intramarginal vein, but it differs in having 

(1) predominantly unoriented, rather than exmedially 

elongate, regions enclosed by the tertiary veins, (2) large 

stomata with well-developed T -pieces, and (3) a pattern 

of subsidiary cell arrangement that typically ranges only 

from laterocytic to cyclocytic. (See Wolfe and others, 

1975 and Hickey and Doyle, 1977 for illustrations of 

foliar architecture in Eucalyptophyllum; see Upchurch, 

1984 for illustrations of stomatal structure.) 

Longstrethia varidentata shows strong similarities 

with six species of Cretaceous age but cannot be assigned 

to any of them because of different foliar architecture 

and/or incomplete preservation of the previously 

described material. Among Early Cretaceous forms, 

Longstrethia most closely resembles "Sapindopsis" elliptica Fontaine (1889, pl. 147, fig. 3) from the Potomac 

32 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Group of Virginia. Characters shared by both species 

include an elongate and nearly oblong shape, highly 

irregular and decurrent secondary venation that is 

organized in a festooned brochidodromous pattern, brochidodromous arches that show a strong tendency to be 

flattened, common intersecondary veins, and tertiary and 

quaternary venation that is poorly differentiated and not 

strongly quadrangular. However, L. varidentata differs 

from "S ." elliptica in having a prominent intramarginal 

vein and in having teeth present in some leaves. 

Longstrethia resembles two species described from 

the Dakota Group. Longstrethia varidentata resembles 

Myrtophyllum warderi Lesquereux (Lesquereux, 1892, 

pl. 53, fig. 10) in having an elongate shape, numerous thin 

secondary veins, and an intramarginal vein, but it differs 

in having a smaller size. In addition, no venation above 

the second order is visible on the holotype of Myrtophyllum warderi, which makes demonstration of conspecificity (and congeneric relationships) impossible because 

tertiary venation is one of the diagnostic features 

separating Longstrethia from Myrtophyllum. L. varidentata also resembles "Eucalyptus" dakotensis Lesquereux 

(1892, pl. 37, figs. 14-19) in size, shape, and presence of 

an intramarginal vein, but it differs in having intercostal 

regions that are flattened, rather than rounded, on their 

exmedial sides. In addition, the type specimens of "E." 

dakotensis have no preserved venation above the second 

order. 

Longstrethia also closely resembles three species 

reported from the Upper Cretaceous Raritan Formation 

of New Jersey. Serrate variants resemble "Celastrus" 

arctica Heer (Newberry, 1895, pl.13, figs. 8-18) in having 

similar laminar shape, secondary venation, and tooth 

shape, but they differ in having a larger size and more 

widely spaced teeth. (On the basis of illustrations of the 

holotype, "C." arctica Heer (1883, pl. 61, figs. 5d, 5e) 

differs from Raritan remains assigned to "C." arctica in 

showing no intramarginal vein.) Entire-margined 

members of Longstrethia resemble "Eucalyptus" angustifolia Newberry (Newberry, 1895, pl. 32, figs. 1, 6, 7) in 

having an oblong shape and irregular secondary veins 

that connect with an intramarginal vein, but they differ in 

their larger size and less linear shape. L. varidentata also 

resembles two specimens of "Eucalyptus" geinitzi Heer 

( =Myrtophyllum geinitzi (Heer) Heer) illustrated by 

Newberry (1895, pl. 32, figs. 2, 12) in shape and 

secondary venation, but the absence of readily visible 

tertiary venation precludes assignment to this species, as 

does cuticular anatomy significantly different from that 

illustrated for Myrtophyllum angustifolium (a probable 

congener of M. geinitzi) by Kvacek (1983). 

Among extant flowering plants, a relationship 

between Longstrethia and Magnoliidae is indicated by the 

combination of poor differentiation between petiole and 

blade, irregular venation, lamellar cuticular thickenings 

Figure 13. Schisandra propinqua (Wall.) 

Baill., U.S.G.S. Ref. Coli. no. 2384, details of 

weakly glandular teeth, x 7.5. 

on the guard cells, epidermal secretory cells that are 

isodiametric and straight -sided, and mesophyll secretory 

cells. A possible relationship with Illiciales is indicated by 

the combination of oval stomata over 30 microns long, 

lamellar cuticular thickenings that form a ring concentric 

to the stomatal pore, T -pieces at the stomatal poles, and 

laterocytic subsidiary cells, a suite of features that 

distinguishes Illiciales from other Magnoliidae (see 

pl. 20, figs. 2-5). In spite of these similarities, Longstrethia differs from extant Illiciales in having an intramarginal vein (compare pl. 18, figs. 2, 7 to pl. 20, 

figs. 6-8), somewhat less quadrangular tertiary venation, 

and poorly developed striations on the cuticle. Also, 

Illiciales with only four orders of venation (Illicium, 

Kadsura) differ from Longstrethia in having highly 

branched freely ending veinlets (pl. 20, fig. 9), and most 

serrate-margined Illiciales have glandular teeth. However, a few Illiciales have only very weakly glandular teeth 

with poorly developed accessory venation (text figure 

13), which indicates that tooth structure in Longstrethia 

may not preclude a relationship to extant Illicales 

An alternative to the above scheme of relationships 

is a close relationship between Longstrethia and extant 

Trimeniaceae. This alternative is based on the presence 

of an intramarginal vein in both taxa, a derived feature 

that within Magnoliidae characterizes Trimeniaceae 

(Laurales). In addition, teeth of Trimeniaceae conform 

to the monimioid type of Hickey and Wolfe (1975), which 

Systematics 33 
I 

I 

I _, 

I ', ' , ;' 

I 

I 

I 

I 

' \ 

' 

B 

....... , 

\ 

\ 

' \ 

\ 

I 

I 

I 

I 

I 

I 

I 

Figure 14. Didromophyllum basingerii new genus and species, x 1. A, 15713-4895, 

specimen shown on plate 21, figure 3, and pl. 22, fig. 2. 8, 15713-4699b, specimen shown 

on plate 21, figure 1, fragment showing details of secondary venation. 

differs from the tooth type of Longstrethia in being 

glandular but is similar in having one or no accessory 

veins. However, phenetic differences between the two 

taxa that typically segregate genera and families of extant 

Magnoliidae imply that the intramarginal vein and 

absence of accessory tooth venation in Longstrethia may 

have originated independently of those in Trimeniaceae. 

Longstrethia differs from Trimeniaceae in having 

(1) irregularly reticulate tertiary venation, (2) nonglandular teeth, and (3) large stomata with T-pieces that 

have predominantly laterocytic, rather than paracytic, 

subsidiary cells. Additional differences between Longstrethia and Trimeniaceae of ambiguous phylogenetic 

significance include ( 4) irregular tertiary venation (a 

presumed primitive feature) and (5) the presence of 

cuticular striations (which are readily evolved in separate 

extant families). 

Longstrethia, therefore, represents an extinct taxon 

of Magnoliidae that shows a possible relationship to 

Illiciales or Trimeniaceae but differs from all extant 

members of Magnoliidae in at least several characters. 

MAGNOLIIDAE order unknown and magnoliid-grade foliage 

Didromophyllum new genus 

Diagnosis.-Laminar units bilobed. Primary venation of each laminar unit consisting of two veins that 

originate from the top of the petiole(ule?) and run along 

the basal margins of the lamina. Secondary veins arising 

only from the apical sides of the primary veins, somewhat 

irregular in course and spacing, festooned brochidodromous. Tertiary and higher order venation irregularly 

reticulate, commonly deflected at points of branching. 

Type species.-Didromophyllum basingerii. 

Derivation of name.-Greek, di =two, dromos = 

course, phyllos =leaf, referring to the presence of two 

primary veins in each lamina. 

Didromophyllum basingerii new species 

Plate 21; plate 22, figures 1-2; text figure 14. 

Diagnosis.-As for genus. 

Description.-Lamina bilobate; distance from the 

base of the lamina to the apical sinus 3-4.5 em; distance 

from the base of the lamina to the tip of each lobe 6-

> 10 em; lobes 1.8-3.5 em wide at the widest point; apex 

of lobes acute; apical sinus rounded; base of lamina 

acutely cuneate, poorly differentiated from the petiole(ule); one complete petiole(ule) preserved, 4.5 em 

long; margin of lamina entire. Primary venation consisting of two primary veins that originate from the top of 

the petiole(ule); one primary vein commonly thicker than 

the other; the smaller primary vein usually somewhat 

decurrent on the larger one; both primary veins running 

along the basal margins of the lamina to the apex of the 

lobes; primary veins thick, diverging at an angle of 

60-100°. Secondary venation originating only from the 

apical side of each primary vein, festooned brochidodromous; secondary veins thin relative to primary veins, at 

least 5-7 per lamina lobe, slightly decurrent on primary 

vein, narrow to moderate acute, tending to zig-zag; 

34 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
brochidodromous junction formed by secondary veins of 

equal thickness, with the superadjacent secondary vein 

deflected apically; angle of brochidodromous junction 

ranging from acute to obtuse; excostal secondary loops 

irregular in size and shape; 1-2 orders of excostalloops 

present between costal loops and margin. Intercostal 

tertiary venation unbranched to reticulate, poorly 

differentiated from the higher order venation; tertiary 

veins thick relative to the secondary veins, diverging at 

acute to right angles on both sides of the secondary veins, 

deflected at points of branching, course and spacing 

variable. Higher order venation poorly differentiated 

from tertiary venation, originating from thin lateral 

branches of the tertiary veins, similar in behavior. Areolation well developed; areoles medium to large, 4-5 

sided; freely ending veinlets in few, if any, of the areoles; 

freely ending veinlets possibly representing an artifact of 

decay. Marginal venation looped, margin with structural 

reinforcement. 

Cuticle poorly preserved, no successful preparations made. 

Number of specimens examined.-12. 

Holotype .-15713-4895. 

Paratypes. -15713-4699a, 4699b, 4699a', 4699b ', 

7863, 7865, 8302. 

Derivation of epithet.-In honor of James Basinger, 

and in recognition of his contributions to this project. 

Discussion.-Didromophyllum basingerii is a highly 

unusual leaf type. In all other angiospermous leaf types 

examined, primary venation conforms to a well-defined 

pattern of symmetry: laminar tissue occurs on both sides 

of a primary vein, and branch veins originate from 

opposite sides of each primary vein. Primary veins, 

therefore, define actual or potential planes of symmetry 

within the lamina. In D. basingerii, laminar tissue occurs 

only on the apical side of each primary vein, and higher 

order veins only originate from the apical side of each 

primary vein. Primary veins, therefore, do not define 

actual or potential planes of symmetry within the lamina. 

The unusual primary venation of Didromophyllum 

shows some similarity to the venation of certain fern taxa 

that have several discrete orders of reticulate venation, 

and in particular Cheiropleuriaceae and Dipteridaceae. 

In these two families, the primary vein of each leaf 

exhibits one or more bifurcations, the secondary venation 

can show strong tendencies for looping (at least in the 

lobes), and the tertiary and higher order venation is 

generally strongly reticulate and encloses quadrangular 

areas. However, Didromophyllum possesses three sets of 

features that are anomalous among extant and fossil 

ferns and that together are more consistent with 

angiospermous affinities. First, the primary venation of 

Didromophyllum does not appear to be truly dichotomous, like that of Cheiropleuriaceae and Dipteridaceae, but it is fundamentally monopodia! in organization: one of the two primary veins is nearly always 

thinner than the other, and this thinner vein arises from 

the thicker vein in a decurrent manner. This pattern is 

characteristic of various mid-Cretaceous angiosperms 

that have bilobed foliage, including "Sassafras" bilobatum Fontaine (1889, pl. 156, fig. 12; pl. 164, fig. 4) and 

"Sterculia" snowii, var. disjuncta Lesquereux (1892, 

pl. 58, fig. 6; see pl. 22, fig. 3 of the present report). 

Second, the secondary veins Didromophyllum are somewhat irregularly spaced, decurrent on the primary veins, 

and enclose regions of variable size and shape. This 

syndrome of features differs from that of Cheiropleuriaceae and Dipteridaceae, where the secondary venation 

is more regular and is not decurrent on the primary veins. 

Third, the tertiary and higher order venation of Didromophyllum is more irregular in its angle of origin and 

shape of enclosed regions than that of comparable ferns, 

which typically have strongly orthogonal tertiary and 

quaternary venation that encloses strongly quadrangular 

regions. These anomalies are consistent with the similarities found between Didromophyllum and the bilobed 

mid-Cretaceous genus Liriophyllum (elaborated below), 

which are taken as evidence of relationship. 

The preservation of Didromophyllum precludes 

determination of whether each laminar unit represents a 

leaf or leaflet. Although each laminar unit shows the 

fundamentally symmetrical organization that characterizes leaves, no specimen preserves the base of the 

petiolar region. In addition, laminar units often occur in 

pairs on the same bedding plane, indicating that they 

might be part of some larger foliar structure. This 

possibility is strengthened by the occurrence of bifurcately compound taxa of Cenomanian age, such as Haliserites Sternberg, F ontainea Newberry (here considered a 

junior synonym of Haliserites ), and "Sterculia" snowii var. 

disjuncta Lesquereux. The most similar of these taxa to 

Didromophyllum isS. snowii var. disjuncta (pl. 22, fig. 3 of 

this report), which consists of two bilobed laminar units 

connected to each other by the base of their petiolules. 

The primary venation of each laminar unit in S. snowii 

var. disjuncta is very similar to that of Didromophyllum in 

consisting of a distinct midvein and a somewhat thinner 

decurrent lateral primary vein and differs only in having 

laminar tissue basal to each primary vein. These 

similarities indicate that the unique pattern of primary 

venation in Didromophyllum may have arisen in the 

following manner: (1) origin of a lateral lobe with a 

decurrent lateral primary vein, then (2) supression of 

laminar development in the region basal to the two 

primary veins. 

If the unique pattern of primary venation and 

possible bifurcately compound organization are excluded 

from consideration, the modern affinities of Didromophyllum appear to be with Magnoliidae, and possibly 

with primitive families of Magnoliales and Laurales. 

Systematics 35 
Among extant angiosperms, the combination of irregular 

festooned brochidodromous secondary venation and 

irregularly reticulate tertiary and quaternary venation is 

most characteristic of Magnoliidae. Within Magnoliidae, 

the suite of venational features characteristic of Didromophyllum is most similar to that of the families Magnoliaceae and Austrobaileyaceae, primitive members of the 

orders Magnoliales and Laurales, respectively. Features 

shared by Didromophyllum, Magnoliaceae, and Austrobaileyaceae include reticulate tertiary venation that 

tends toward quadrangular, higher order venation that 

usually encloses quadrangular or isodiametric regions, 

and well-developed areolation. Didromophyllum more 

closely resembles Magnoliaceae in having exmedially 

elongate, predominantly straight-sided intercostal 

regions, tertiary venation with a stronger transverse than 

admedial component, and a margin with strong mechanical reinforcement (rather than a fimbria! vein), but 

Didromophyllum more closely resembles Austrobaileyaceae in having areoles with few freely ending veinlets. 

These similarities between Didromophyllum, Magnoliaceae, and Austrobaileyaceae are reinforced by similarities between Didromophyllum and two fossil genera: 

(1) Ficophyllum, a genus with close similarities in foliar 

architecture to extant Winteraceae, Magnoliaceae, and 

Austrobaileyaceae (Upchurch, 1983), and (2) Liriophyllum, a genus associated with floral remains showing 

strong similarity to the flowers of extant primitive angiosperms, such as Degeneriaceae, Magnoliaceae, and Austrobaileyaceae (Dilcher and Crane, 1984). In particular, 

the straight-sided, exmedially elongate intercostal 

regions and syndrome of tertiary and higher order venationa! features found in Didromophyllum resemble what 

is found in Ficophyllum and Liriophyllum, and Didromophyllum strongly resembles Liriophyllum in having a 

pattern of higher order venation that is similar in its 

degree of organization. Thus, Didromophyllum appears 

to represent a taxon of early angiosperms that may be 

related to primitive families of extant Magnoliales and 

Laurales, but it possesses a highly divergent, "experimental" pattern of foliar organization with no close 

modern counterpart. 

Acritodromum new genus 

Diagnosis.-Leaf simple, margin entire and with 

structural reinforcement, base acute. Primary venation 

pinnate. Secondary venation festooned brochidodromous, secondary veins irregular in their course and 

spacing. Tertiary venation reticulate; tertiary veins also 

irregular in course and spacing but showing a definite 

tendency to be closely spaced and oriented subparallel to 

the midrib, commonly curved or sinuous. Quaternary 

venation unbranched to reticulate, quaternary veins 

irregular in their behavior. 

Figure 15. Acritodromum ellipticum new 

genus and species, 1571-4704, specimen 

shown on plate 23, figures 1-3, illustrating 

spacing of the secondary veins, x 1. 

Type species.-Acritodromum e/lipticum. 

Derivation of name.-Greek, akritos =disorderly, 

dromos = course, referring to the irregular course and 

spacing of the secondary and higher order venation. 

Acritodromum elliptlcum new species 

Plate 23, figures 1-3; text figure 15 

Diagnosis.-As for genus. 

Description.-Lamina elliptic but bordering on 

subrhomboidal, L/W over 4; lamina over 8 em long by 

about 2 em wide (estimated width); apex unknown 

(perhaps attenuate); base acute; petiole unknown; 

margin entire. Primary venation pinnate; primary vein 

massive, curved. Secondary venation festooned brochidodromous; secondary veins thin, more than four pairs, 

alternate, irregularly spaced and with the median 2 em of 

the leaf having no secondary veins, diverging at narrow to 

broad acute angles in a non-uniform manner, irregular in 

course; basalmost pairs of secondary veins looping well 

within the margin, the others not looping until at least 

two-thirds of the way to the margin; the superadjacent 

secondary vein thicker than the subadjacent secondary 

vein at their junction and not deflected apically; angle of 

brochidodromous junction obtuse except in the 

basalmost pairs of secondary veins, where it is acute; 

excostal secondary loops irregular in size and shape. 

Intersecondary veins present, none or 1 per intercostal 

36 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
region, irregular in course, branching into tertiary veins. 

Tertiary venation irregularly reticulate; tertiary veins 

thick relative to the secondary veins, originating at obtuse 

angles on the exmedial side of the secondary veins and at 

acute angles on the admedial side, often curved, 

enclosing regions of highly variable shape that usually are 

elongate and oriented nearly parallel to the primary vein. 

Quaternary venation unbranched to reticulate non- ' orthogonal; quaternary veins irregular in course and 

spacing, the few preserved unbranched veins tending to 

enclose regions that are slightly elongate and oriented 

oblique to nearly perpendicular to the tertiary veins. 

Marginal venation obscure, possibly consisting of a weak 

fimbria} vein formed from flattened loops. 

No cuticular preparations made. 

Number of specimens examined.-!. 

Holotype.-15713-4704a. 

Derivation of epithet.-Latin, ellipsis= ellipse, 

referring to the elliptical laminar shape. 

Discussion .-Acritodromum differs from other 

Cretaceous taxa of elongate, entire-margined foliage by 

showing high variation in the spacing and angle of 

departure of secondary veins and by showing unique 

patterns of tertiary and quaternary venation. Among 

Early Cretaceous angiosperms,Acritodromum resembles 

Rogersia Fontaine (1889), Saliciphyllum Fontaine (1889), 

and "Sapindopsis" elliptica Fontaine (1889) in having 

~esto?ned ?roc~idodromous secondary venation organtz~d m. a htghly trreg~lar manner, but it differs in having 

Wider mtercostal regiOns, tertiary venation that shows a 

definite tend~ncy to enclose elongate regions, and 

quaternary vems that tend to be unbranched. Among 

Cenomanian angiosperms, Acritodromum resembles 

Pabiania in having closely spaced tertiary veins that show 

tendencies to be parallel and resembles both Pabiania 

and Pandemophyllum in having an entire margin with 

structural reinforcement and non-orthogonally rooted 

quaternary veins that are typically unbranched. In 

addition, the subrhomboidal laminar shape found in 

Acritodromum is rarely encountered in extant angiosperms but is similar to what is found in some specimens 

of Pandemophyllum kvacekii. However, Acritodromum 

differs from these taxa in having much more irregular 

secondary and tertiary venation, and hence appears to be 

more primitive. 

The modern affinities of Acritodromum appear to 

lie with Magnoliidae, but ordinal affinities within the 

subclass are unclear. Among extant angiosperms, the low 

regularity of venation found in Acritodromum characterizes Magnoliidae. Within Magnoliidae, no extant 

family or order possesses the suite of features fo·und in 

Acritodromum. For example, curved primary veins occur 

in scattered Magnoliidae, such as Idiospermaceae, 

Canellaceae, and certain Winteraceae, but none of these 

groups possesses the suite of higher order venational 

features diagnostic of Acritodromum. The extremely 

variable course and spacing of the secondary venation 

found in Acritodromum is a syndrome of features 

postulated as primitive for the flowering plants as a whole 

(Wolfe and others, 1975; Hickey and Doyle, 1977) and 

hence cannot be used as evidence of phyletic relationship. 

The syndrome of tertiary and quaternary venational 

features in Acritodromum also has no close counterparts 

in extant flowering plants, although points of resemblance exist with Myristicaceae, particularly in the tendency for the veins to enclose elongate regions. The 

similarities previously noted between Acritodromum and 

the fossil genera Pabiania and Pandemophyllum could 

indicate a relationship with extant Laurales, but much 

more needs to be learned about this problematic taxon 

before relationships can be determined accurately. 

Reynoldsiopbyllum new genus 

Diagnosis.-Leaf simple; base acute; petiole poorly 

differentiated from blade, less than 1 em long; margin 

broadly crenate and with mechanical reinforcement. Primary venation pinnate. Secondary venation festooned 

brochidodromous; secondary veins zig-zag to sinuous in 

course; intercostal regions somewhat elongate exmedially but never more than several times as tall as broad· ' exmedial margins of the intercostal regions poorly 

demarcated by the secondary veins. Tertiary venation 

irregularly reticulate; tertiary veins thick relative to 

secondary veins, with a zig-zag course, dividing each 

intercostal region into a series of segments. Quaternary 

ve~ation poorly differentiated from the tertiary venation, 

reticulate. Larger crenations typically with a medial vein 

and sometimes with a pair of accessory veins that 

converge on the margin and fuse with the thickening at 

the tooth apex. 

Type species.-Ilex masonii Lesquereux (1892, 

p. 179, pl. 7, fig. 6; pl. 63, fig. 6) 

Derivation of name.-ln honor of Howard Reynolds and in recognition of his invaluable assistance to 

our research on Dakota angiosperms. 

Reynoldsiopbyllum masonii (Lesquereux) new combination 

Plate 23, figures 4-6; text figure 16. 

flex masoni Lesquereux, 1892, U.S. Geological Sutvey 

Monograph 17, p. 179, pl. 6, fig. 6; pl. 63, fig. 6. 

Emended diagnosis.-Leaf 4-5 em wide, L/W 3-4; 

crenations 2-10 mm wide by up to 4 mm tall; marginal 

thickening most strongly developed at the apex of each 

crenation. Secondary veins moderate relative to primary 

veins; superadjacent secondary vein always thicker than 

the subadjacent secondary vein at their point of junction; 

angle of brochidodromous junction ranging from broad 

Systematics 37 
Figure 16. Reyno/dsiophyllum masonii 

(Lesquereux) new combination, USNM 

50077, details of tooth shown on plate 23, 

figure 5, x 7.5. 

acute to obtuse. Orientation of tertiary venation ranging 

from transverse to nearly perpendicular to midvein; 

tertiary veins distinctly thinner than secondary veins. 

Description.-Lamina oblong, L/W 3-4; leaf 12-

15 em long (estimated) by about 4.5 em wide; apex 

obtuse; base acutely cuneate; margin broadly crenate; 

crenations 2-10 mm wide by up to 4 mm tall; sinuses 

broad, obtuse, rounded, and tending to be asymmetric in 

shape. Primary venation pinnate; primary vein stout to 

massive. Secondary venation festooned brochidodromous; secondary veins thin to moderate relative to primary vein, 9-10 pairs, subopposite to alternate, 

irregularly spaced, originating at predominantly moderate to broad acute angles, with a non-uniform pattern 

of variation in divergence angle, zig-zag to somewhat 

curved in course, looping well within the margin; subadjacent secondary vein thinner than the superadjacent 

secondary vein at their point of junction, with the superadjacent secondary vein often deflected apically; angle of 

brochidodromous junction broad acute to obtuse; excostal branches of secondary veins tending to form discrete 

series of loops parallel to the superadjacent secondary 

vein; exmedial sides of excostal secondary loops ranging 

from strongly angular to curved. Intersecondary veins 

absent. Tertiary venation irregularly reticulate; tertiary 

veins half to two-thirds the thickness of the secondary 

veins, tending to divide the intercostal regions into 

transverse to oblique segments, originating at acute to 

right angles on the exmedial side of the secondary veins 

and broad acute to obtuse angles on the admedial side, 

course irregular, giving rise to thinner lateral branches. 

Marginal reinforcement strongly developed, probably 

consisting of a fimbria! vein, marginal thickening usually 

widest and thickest at the apex of each crenation, 

suggesting that the apex of each crenation may be 

glandular. Each crenation with a medial vein, some of the 

large crenations with one or two accessory veins that 

converge on the margin and fuse with the thickened apex; 

tooth architecture possibly representing a variant of the 

chloranthoid type of Hickey and Wolfe (1975). 

Cuticle not preserved on specimens. 

Number of specimens examined.-2. 

Holotype.-VSNM 50077. 

Paratype.-USNM 2779. 

Locality.-Near Pipe Creek, Cloud County, Kansas 

(locality from Lesquereux, 1892). 

Discussion.-Lesq uereux originally assigned this 

species to the genus !lex (Aquifoliaceae ). However, 

detailed examination of foliar architecture indicates that 

this assignment is incorrect. In extant Aquifoliaceae, the 

leaf margin is either entire or serrate (never strongly 

crenate), the secondary veins are less zig-zag in course, 

the intercostal regions have much better defined exmedial margins, and the tertiary venation shows features 

different from those in Reynoldsiophyllum. Further, 

serrate-margined leaves of Aquifoliaceae have teeth that 

either are symmetric and spinose (for example, !lex 

dipyrena) or are strongly asymmetric, with an eccentric 

medial vein, no accessory veins, and a non-deciduous 

glandular seta on the tooth apex (most species of Ilex). 

These patterns conform to the spinose and celastroid 

tooth types of Hickey and Wolfe (1975), respectively. 

The tooth architecture of Reynoldsiophyllum differs in 

several features and conforms most closely to the chloranthoid tooth type of Hickey and Wolfe (1975). 

Reynoldsiophyllum masonii is distinct from all 

previously described taxa but shows similarities with four 

species. R. masonii resembles "Myrica" aspera Lesquereux (1892, p. 66, pl. 2, fig. 11) in shape and marginal 

pattern but is larger and has more prominent crenations; 

further, "Myrica" aspera preserves no venation above the 

first order. R. masonii resembles "Celastrophyllum" 

crenatum Heer, a species reported from the Patoot flora 

of Greenland (Heer, 1874, p. 41, pl. 62, fig. 1) and the 

Raritan Formation of New Jersey (Newberry, 1895, p. 99, 

pl. 48, figs. 1-19), and Celastrophyllum undulatum Newberry from the Raritan Formation of New Jersey (Newberry, 1895, p. 102, pl. 38, figs. 1-3), in shape and general 

pattern of secondary venation, but R. masonii differs in 

having more widely spaced secondary veins that enclose 

broader intercostal regions and show a more zig-zag 

course. In terms of tooth architecture, R. masonii 

strongly resembles Crassidenticulum decurrens in having 

a fundamentally chloranthoid pattern of venation 

combined with well-developed mechanical thickening at 

38 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Figure 17. Reynoldsiophyllum nebrascense new species, 15713-4876, specimen 

shown on plate 24, figures 3 and 5, x 3. The 

stippled circular area adjacent to the midrib 

represents a fossil root that penetrates the leaf 

vertically. 

the apex. However, R. masonii differs from C. decun-ens 

in having broader intercostal regions, no intersecondary 

veins, and tertiary venation that tends to divide each 

intercostal region into a series of segments. 

Because the tertiary and quaternary venation are 

better preserved in Reynoldsiophyllum nebrascense, modern affinities are discussed under that species. 

Reynoldsiophyllum nebrascense new species 

Plate 24; text figure 17 

Diagnosis.-Lamina under 4 em wide, L/W over 4; 

crenations 3-4 mm wide by less than 1 mm tall; marginal 

reinforcement showing no variation in width along the 

length of each crenation. Secondary veins thin relative to 

primary vein; superadjacent secondary vein usually equal 

in thickness to the subadjacent secondary vein at their 

point of junction, forming an acute angle. Orientation of 

tertiary venation typically transverse; tertiary veins nearly 

as thick as the secondary veins. 

Description.-Lamina narrow elliptic, nearly 

oblong, L/W well over 4; lamina well over 8 em long by 

about 1.8-2.5 em wide; apex not fully preserved but 

probably obtuse or rounded; base acutely cuneate; 

petiole poorly differentiated from the blade; margin 

broadly crenate and with mechanical reinforcement; 

crenations 3-4 mm wide and less than 1 mm tall; sinuses 

broadly obtuse, rounded. Primary venation pinnate; primary vein stout. Secondary venation predominantly 

festooned brochidodromous, but intergrading with the 

condition where the secondary veins curve apically, thin, 

and merge with the tertiary venation; secondary veins 

thin relative to the primary vein, more than 8 pairs, 

subopposite to alternate, irregularly spaced, predominantly moderate to broad, rarely narrow, acute; course 

apically curved and often with deflection at points of 

branching; brochidodromous junction formed by two 

secondary veins of equal thickness, with the superadjacent secondary vein often deflected apically; angle of 

brochidodromous junction almost always acute; excostal 

secondary veins forming a complete inner and incomplete outer series of loops, these poorly differentiated 

from the tertiary venation, outer sides of loops tending 

towards rounded, in the outermost loops appearing to 

merge with the marginal thickening. Intersecondary veins 

absent. Tertiary venation irregularly reticulate; tertiary 

veins thick relative to the secondary veins and in excostal 

regions often difficult to distinguish from secondary 

veins, tending to divide the intercostal regions into a 

series of transverse segments, originating at acute to 

right-angled on the exmedial side of the secondary veins 

and obtuse to right-angled on the admedial side, composed of trunk veins and thick lateral branches that 

anastomose in an unpredictable pattern. Quaternary 

venation poorly differentiated from the tertiary venation, 

reticulate; quaternary veins often curved. 

part). 

Cuticle poorly preserved, no preparations made. 

Number of specimens examined.-4. 

Holotype.-15713-1805, 7805' (part and counterParatype.-15113-4816, 4876' (part and counterpart). 

Derivation of epithet.-Referring to the occurrence 

of this species in Nebraska. 

Discussion.-Four specimens from Rose Creek 

belong to Reynoldsiophyllum nebrascense. The holotype 

preserves nearly a complete leaf. The paratype comprises 

the middle portion of a leaf and lacks an apex and base, 

and the other specimens lack an apex, base, and margin 

but are identical to the first two specimens in preserved 

venational features. Reynoldsiophyllum nebrascense is 

distinguished from R. masonii by its smaller size 

(especially width), smaller and less prominent crenations, 

thinner secondary veins that are of equal thickness and 

form predominantly acute angles at their brochidodromous junctions, narrower intercostal regions, and thicker 

tertiary veins that have a more transverse orientation. R. 

nebrascense strongly resembles "Myrica" aspera in its size 

and shape but appears to have more numerous crenations; further, M. aspera preserves no venation above the 

first order, making demonstration of conspecificity 

impossible. R. nebrascense also resembles Celastrophyllum crenatum and C. undulatum in general shape and 

marginal type but is smaller and more elongate. 

Systematics 39 
The modern affinities of Reynoldsiophyllum appear 

to lie with Magnoliidae, and similarities in tooth architecture with Crassidenticulum decurrens imply possible 

affinities with Chloranthaceae. Among extant angiosperms, the combination of pinnate organization, 

festooned brochidodromous secondary venation that has 

irregular course and spacing, and irregularly reticulate 

tertiary venation are most consistent with an assignment 

to Magnoliidae, although none of the characters represents a derived feature restricted to the subclass. Within 

extant Magnoliidae, the combination of transverse 

reticulate tertiary venation and chloranthoid teeth is 

restricted to Illiciales and certain Chloranthaceae ( Chloranthus and Sarcandra). However, Reynoldsiophyllum 

does not possesses the curved and highly ramified 

quaternary venation that characterizes extant Illiciales 

with comparable venational regularity, and Reynoldsiophyllum differs from Illiciales in having well-developed 

marginal reinforcement over the teeth. Reynoldsiophyllum also is unlike Chloranthus and Sarcandra in 

quaternary venation (significantly thicker and not as 

strongly ramified), tooth shape (more rounded), and 

marginal thickenings (significantly better developed and 

not restricted to the region over the gland); however, 

many of these features occur in other genera of Chloranthaceae, indicating a possible relationship. This possibility is strengthened by similarities between Reynoldsiophyllum and the fossil taxon Crassidenticulum 

decurrens, especially with respect to features of systematic importance in extant flowering plants at higher 

taxonomic levels. These include pinnate organization, a 

tendency for the exmedial sides of the intercostal regions 

to be poorly demarcated by secondary veins, excostal 

secondary loops that range from angular to strongly 

curved on their exmedial sides, reticulate tertiary and 

quaternary venation, commonly curved quaternary veins, 

and teeth with chloranthoid venation that can be strongly 

crenate and have well-developed structural reinforcement, especially at the tooth apex. Of these features, the 

syndrome of tooth characters is unusual within extant 

angiosperms and, together with the other similarities, 

provides evidence for a close relationship between the 

two taxa. Thus, Reynoldsiophyllum may show affinities 

with Chloranthaceae but differs from extant members of 

the family in several foliar features, most notably the 

occurrence of mechanical reinforcement over the entire 

length of the tooth. 

Dicotylophyllum angularis new species 

Plate 25, figures 2-3; text figure 18 

Diagnosis.-Lamina ovate, L/W 2.7 to at least 3; 

lamina > 5 em long by 1.8-3 em wide; apex attenuate; 

Figure 18. Dicotylophyllumangularis, 15713-

4882A, specimen shown on plate 25, figures 2 

and 3, x 1. 

base acutely cuneate. Primary venation pinnate; primary 

vein consisting of separate strands. Secondary venation 

festooned brochidodromous; secondary veins sharply 

changing course when forming loops; intercostal regions 

more or less isodiametric above the base of the lamina. 

Laminar resin bodies present. 

Description.-Lamina symmetric or more rarely 

slightly asymmetric, ovate, L/W 2.7 to at least 3; lamina 

> 5 em long by 1.8-3 em wide; apex attenuate; tip of leaf 

not preserved; base acutely cuneate; petiolar region 

poorly differentiated from blade; margin entire, with 

structural reinforcement. Primary venation pinnate; primary vein moderate to stout, usually several-stranded at 

base, with fewer strands apically. Secondary venation 

festooned brochidodromous; secondary veins thin 

relative to primary vein, about as thick as an individual 

primary vein strand, at least 5 pairs, generally alternate, 

with wide but irregular spacing, with predominantly 

moderate acute divergence angles, curving little until at 

least halfway to the margin, typically making a sharp bend 

just before connecting with the superadjacent secondary 

vein; secondary vein looping tending towards angular, 

brochidodromous junction formed by two secondary 

veins of equal thickness, with the superadjacent secondary vein deflected apically; intercostal regions mostly 

isodiametric; excostal branches of the secondary veins 

forming a complete series of loops. Higher order venation poorly preserved. Laminar resin bodies present, 

interpreted as the remains of secretory cells. 

Cuticle preserved along the margin and midvein of 

some specimens, but with the upper and lower cuticle 

40 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
adhering together tightly in preparations, making observation of cellular features impossible. 

Number of specimens examined for foliar 

architecture.-5. 

Number of specimens examined for cuticular 

anatomy. -1. 

Holotype. -15713-4882A. 

Derivation of epithet.-Latin, angularis = diminutive of angulus, or corner, referring to the sharp bend 

made by the secondary veins before forming loops. 

Discussion.-Despite incomplete preservation 

Dicotylophyllum angularis is distinct from previously 

described species of Cretaceous angiosperms. Among 

Rose Creek forms it most closely resembles Landonia 

calophylla, from which it differs in shape and details of 

venation. D. angularis shows little resemblance to any 

previously described species of angiosperm leaves, 

despite the small number of preserved features. 

Dicotylophyllum angularis appears to represent 

Magnoliidae, although few preserved features can be 

used for systematic placement. In particular, the 

combination of a several-stranded midvein and laminar 

resin bodies appears to be restricted to Magnoliidae. If 

an assignment to Magnoliidae is accepted, then Dicotylophyllum angularis probably belongs to Laurales, 

because the combination of a strongly ovate shape and 

isodiametric intercostal regions only occurs in Laurales 

of primitive to intermediate status, such as Amborellaceae, Austrobaileyaceae, and Monimiaceae. More 

definite consideration of the systematic position of Dicotylophyllum angularis awaits discovery of better preserved 

specimens. 

New Genus B 

Plate 25, figures 4-6; text figure 19 

Description.-Lamina symmetric to slightly asymmetric, oblong, L/W well over 3; lamina well over 3 em 

long by 1-2.4 em wide (estimated maximum width); apex 

and base missing; margin entire, with structural 

reinforcement. Primary venation pinnate; primary vein 

massive, possibly multistranded. Secondary venation 

festooned brochidodromous; secondary veins thin, more 

than 5 pairs, ranging from alternate to subopposite, 

irregularly spaced, decurrent on primary vein, with 

irregular divergence angles ranging from narrow to 

broad acute, often sinuous, looping near the margin; 

loops often flattened parallel to margin; brochidodromous junction formed by secondary veins of equal 

thickness, with the superadjacent secondary vein 

deflected apically; intercostal regions highly variable in 

shape; excostal branches of the secondary veins poorly 

preserved but appear to extend to margin. IntersecondFigure 19. New genus B, 15713-4850, 

specimen shown on plate 25, figures 4 and 6, 

x3. 

ary veins present, 0 or 1 per intercostal region, branching 

to form tertiary veins. Tertiary venation irregularly 

reticulate; tertiary veins thick relative to the secondary 

veins, originating at acute to right angles on both sides of 

the secondary veins, course and spacing highly irregular 

but with a slight tendency for transverse orientation. 

Cuticle not preserved, no preparations made. 

Number of specimens examined.-2. 

Specimens.-15713-4831, 4831' (part and counterpart), 4850. 

Discussion.-Although this taxon differs from all 

previously described species of mid-Cretaceous angiosperms, fragmentary preservation precludes formal 

diagnosis. Among previously described fossil genera, 

New genus B resembles Rogersia Fontaine (1889) in size, 

shape, and venational regularity but differs in having less 

apically oriented secondary veins. New genus B also 

resembles Eucalyptophyllum Fontaine and Myrtophyllum 

Heer in having an oblong shape but differs in having 

secondary veins that form loops (rather than connect 

with an intramarginal vein) and in having less strongly 

oriented tertiary venation. 

The high irregularity of the secondary and tertiary 

venation in New genus B is suggestive of magnoliid 

affinities, but incomplete preservation and predominance 

of generalized venational features makes systematic 

placement difficult. 

Systematics 41 
Subclass ROSIDAE 

Anisodromum new genus 

Diagnosis.-Leaf compound, lamina of each leaflet 

elliptic, base acute, with a distinct petiolule present on 

each leaflet, margin entire. Primary venation pinnate. 

Secondary venation tending toward eucamptodromous 

but with tendencies to form brochidodromous loops; 

secondary veins originating at an angle greater than 45°, 

distinctly asymmetric in behavior, with the secondary 

veins on one side of the lamina either diverging from the 

midvein at a higher angle or curved for a greater proportion of their length; each secondary vein producing its 

own series of weakly formed brochidodromous loops that 

extends to near the margin. Tertiary venation weakly 

percurrent; tertiary veins thin, closely spaced, with low 

angle branching, oriented at nearly a right angle to the 

midrib. 

Type species .-Anisodromum wo/fei new species. 

Derivation of name.-Greek, anisos =unequal, 

dromos =course, referring to the asymmetry of the 

secondary venation. 

Anisodromum wolfei new species 

Plate 26; text figure 20 

Diagnosis.-As for genus. 

Description.-Leaf compound, with at least three 

leaflets; lamina of leaflets narrow elliptic, L/W over 2; 

lamina > 4.5 em long by 2-4 em wide; apex unknown; 

base acutely cuneate; petiolule present, up to 2 em long; 

margin entire, with structural reinforcement. Primary 

venation of each leaflet pinnate; primary vein stout. 

Secondary venation smoothly curving and gradually 

thinning near margin but showing a tendency to form 

loops (therefore, predominantly eucamptodromous but 

with brochidodromous tendencies), asymmetric in 

behavior, with the secondary veins on one side of the 

lamina diverging from the primary vein at a higher angle 

and/or curving for a greater proportion of their length; 

secondary veins moderate relative to the primary vein, 

more than 8 pairs, subopposite, tending to be evenly 

spaced, moderate to broad acute, apically curved, 

extending to near the margin. Intersecondary veins 

absent. Tertiary venation percurrent; tertiary veins thin 

relative to the secondary veins, usually forming an acute 

angle on the exmedial side of the secondary veins and 

right or obtuse angle on the admedial side, typically 

branching at narrow acute angles, in most specimens 

oriented at nearly right angles to the midvein of the 

leaflet. 

Cuticle not preserved. 

Number of specimens examined.-6. 

Ho/otype. -15713-7803. 

Figure 20. Anisodromum wolfei new genus 

and species, 15713-7866, x 2. The dark 

circular region on the lower right represents a 

fossil root that penetrates the leaflet vertically. 

Paratypes.-15113-1802, 7866. 

Derivation of epithet.-In honor of Jack A. Wolfe 

and in recognition of his assistance to this project. 

Discussion.-Among previously described genera 

of fossil angiosperms Anisodromum most closely 

resembles Sapindopsis, especially pinnately compound 

leaves assigned to this genus by Doyle and Hickey (1976) 

and Hickey and Doyle (1977), in shape and general 

pattern of venation. However, Anisodromum differs in 

having secondary venation that shows asymmetric 

behavior and much less brochidodromous looping, much 

more percurrent and closely spaced tertiary venation, 

and a structurally reinforced margin. We interpret these 

differences as significant at the generic level by analogy to 

extant pinnately compound Rosidae, where genera are 

distinguished on the basis of secondary venation, tertiary 

venation, and marginal characteristics. 

Among previously described species of fossil 

angiosperm foliage Anisodromum wolfei resembles 

several species of pinnately compound leaves that have 

thin, apically curved secondary veins, including "Rhus" 

powel/iana Lesquereux (1892, pl. 56, fig. 45), "Rhus" 

uddeni Lesquereux (1892, pl. 57, fig. 2) and "Hymenaea" 

dakotana Lesquereux (1892, pl. 55, figs. 2, 3; pl. 56, 

figs. 1, 2; pl. 62, fig. 2). Anisodromum wolfei differs from 

these species in having asymmetrical secondary venation 

and in having the following combination of features: 

(1) leaflets with a distinct petiolule, and (2) closely 

spaced tertiary veins that are oriented at nearly right 

angles to the midvein. A. wolfei also resembles isolated 

laminar units described as Leguminosites hymenophyllus 

Lesquereux (1892, pl. 55, figs. 7-9; pl. 56, fig. 3) but 

differs in having asymmetrical secondary venation. 

42 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
A. wolfei strongly resembles isolated laminar units 

assigned to "Rhamnus" pnmifolius Lesquereux (1874, 

illustrated in Lesquereux, 1892, pl. 35, fig. 14) in 

secondary and tertiary venation but has an elliptic, rather 

than ovate, shape and asymmetrical secondary venation. 

Finally, A. wolfei resembles isolated laminar units 

described as ''Andromeda" latifolia by Newberry (1895, 

especially pl. 34, figs. 6-11) in shape and pattern of 

secondary and tertiary venation, but it differs from ''A." 

latifolia in having asymmetrical secondary venation that 

is oriented at a higher angle to the midrib. 

The modern affinities of Anisodromum clearly lie 

with the subclass Rosidae. Among extant dicotyledons, 

compound foliage is restricted to the subclasses Ranunculidae, Rosidae, Dilleniidae, and Asteridae. Of these 

subclasses, only Rosidae has compound leaves where the 

secondary venation of each leaflet has distinct asymmetry.Anisodromum does not fit within any extant order 

of Rosidae because it combines features currently 

restricted to separate orders.Anisodromum has the compound organization characteristic of Sapindales, Rutales, 

and certain taxa of Saxifragales and Rosales; however, its 

pattern of tertiary venation is unknown in these groups. 

Instead, the general pattern of tertiary venation found in 

Anisodromum characterizes many simple-leaved members of Rosidae, most notably Cornales, Rhamnales, 

certain Celastrales (some Celastraceae and Icacinaceae) 

and Santalales ( 0 lacaceae ), and some simple-leaved 

families of Saxifragales (most notably Escalloniaceae and 

Iteaceae). These simple-leaved taxa typically have more 

widely spaced tertiary veins thanAnisodromum, but some 

pinnately veined Rhamnaceae (Berchemia, Rhamnidium, 

and Rhamnus), Celastraceae (Bhesa), Icacinaceae 

(Emmotum) and Olacaceae (Coula) have tertiary venation with the same close spacing and orientation relative 

to the midrib, typically in association with strongly 

eucamptodromous secondary venation. The venational 

similarities between Anisodromum and extant Rhamnaceae are of particular interest because the flowers 

reported from the Rose Creek locality by Basinger and 

Dilcher (1984) combine generalized features found in 

Rosidae and other subclasses with specialized features 

most characteristic of Rhamnales (especially stamens 

opposite the petals and small tricolporate pollen grains 

with an oblate shape and psilate surface sculpture). This 

combination of features today found in different orders 

of Rosidae, when coupled with evidence for the 

derivation of Citrophyllum from a compound-leaved 

ancestor (described later), provides direct paleobotani~al 

evidence for a phylogenetic link between the two maJor 

alliances of Rosidae (Hickey and Wolfe, 1975). 

Citrophyllum Berry, 1911b. 

Emended Diagnosis.-Leaf simple, lamina unlobed, petiole alate, constricted at the base of the lamina, 

' ') 

I 

I ' 

I ' 

I ' 

I 

\ 

\ 

I 

' \ 

---

Figure 21. Citrophyllum doylei new 

species, 15713-4894, specimen shown on 

plate 27, figures 1, 3, and 4, x 2. Note the 

eucamptodromous secondary veins and the 

closely spaced tertiary veins with low-ang~e 

branching. The raggedness of the marg1n 

results from differential preservation of the 

reinforcement tissue. 

margin entire, structurally reinforced. Primary venation 

pinnate. Secondary venation often faintly visible or 

absent on impressions; secondary veins originating at an 

acute angle greater than 45°; intercostal regions exmedially elongate, apically curved. Tertiary and higher order 

venation more or less immersed in the laminar tissue, 

when preserved at least in part reticulate. 

Type species.-Ficus aligera Lesquereux, 1892, 

p. 84, pl. 10, figs. 3-6. . 

Species included within Citrophyllum.-C. allgerum 

(Lesq.) Berry, 1911b, p. 169, pl. 21, figs. 1-8. Upper 

Cretaceous, Dakota and Raritan Formations, USA. 

C. doylei new species. Upper Cretaceous, Dakota 

Formation, USA. 

Citrophyllum doylei new species 

Plate 27, figures 1, 3, 4; text figure 21 

Diagnosis.-Lamina mesophyllous in size. Alation 

on petiole parallel-sided for nearly all its length, abruptly 

constricted at base of lamina. 

Description.-Basal two-thirds of leaf preserved, 

L/W well over 2; lamina significantly longer than 8.5 em 

by about 5 em wide (estimated wi~th); apex missi~g; b~se 

obtuse, bordering on rounded, slightly asymmetnc, With 

the two sides of the lamina joining the midrib at slightly 

different levels; petiole at least 0.9 em long by 0.3 em 

wide, with margins that are more or less parallel up_ to the 

point of constriction. Primary vein stout, bordenng on 

Systematics 43 
moderate. Secondary venation eucamptodromous; secondary veins moderate relative to the primary vein, more 

than 6 pairs, subopposite to alternate, sometimes slightly 

decurrent on the primary vein, originating at a broad 

acute angle, apically curved for most of their length. 

Tertiary venation at least in part reticulate; tertiary veins 

thin relative to the secondary veins, originating at an 

acute angle on the exmedial side of the secondary veins 

and an obtuse angle on the admedial side, oriented nearly 

perpendicular to the primary vein, closely spaced (about 

10 veins per em), subparallel, straight to slightly curved 

or sinuous, often branching at a low acute angle. Higher 

order venation poorly preserved. 

Cuticle poorly preserved, no preparations 

attempted. 

Number of specimens examined.-1. 

Holotype. -15713-4894. 

Derivation of name.-In honor of James A. Doyle 

and in recognition of his numerous contributions to our 

understanding of early flowering plants. 

Discussion.-Citrophyllum is distinguished from 

other genera of Cretaceous angiosperm leaves by the 

combination of an unlobed lamina with a structurally 

reinforced margin, an alate petiole that is constricted at 

its junction with the lamina, and pinnate venation. 

Although the genus was assigned to Rutaceae and compared with exant Citrus by Berry (1911b), Citrophyllum 

does not possess the following features that characterize 

Rutaceae: (1) a joint at the junction of the petiole and 

blade in simple leaves, (2) straight-sided intercostal 

regions, (3) widely spaced tertiary venation, and ( 4) large 

laminar secretory cavities, which in fossil material would 

be preserved as dark spots or as empty regions around 

which the higher order veins ramify. Therefore, the 

assignment of Citrophyllum to Rutaceae is invalid. 

The one specimen of Citrophyllum doylei known 

from Rose Creek represents a new species, which differs 

from remains assigned to C. aligera (Lesq.) Berry in 

having a larger size, a more abrupt constriction of the 

petiole, and more strongly curved secondary venation. 

The orientation of the tertiary venation in Citrophyllum 

doylei also differs from that illustrated by Lesquereux for 

the type species (Lesquereux, 1892, pl. 20, figs. 3-6), but 

the type specimens lack clearly observable tertiary venation. The type specimens of C. aligera examined from the 

Dakota and Raritan Formations can be divided into at 

least two groups based on the shape of the petiole and 

blade, which implies that three species of Citrophyllum 

may have been present in the earliest Late Cretaceous of 

North America. 

The alate petiole of Citrophyllum, with its 

constriction at the base of the lamina, previously has been 

interpreted as the homologue of a rachis in a compound 

leaf and hence evidence of a compound-leaved ancestry 

(Berry, 1911b; Hickey, 1978). Some simple-leaved taxa 

of presumed compound-leaved ancestry, such as Citrus in 

the Rutaceae, have an alate petiole with a constriction at 

the lamina-petiole junction, similar to the constriction of 

the alate rachis of a compound leaf at points of leaflet 

origin. This comparison is supported by similarities in the 

secondary and tertiary venation of Citrophyllum and 

Anisodromum, the latter of which represents a compound 

leaf. The absence of a constriction at the junction of the 

petiole and blade in families, such as Winteraceae and 

Canellaceae, which are of presumed simple-leaved 

ancestry, adds further support to this interpretation. One 

potential problem with this scheme of homology is that 

all known specimens of Citrophyllum appear to lack a 

joint at the junction of the petiole and blade, a feature 

that is present in extant Citrus and is thought to be the 

homologue of the joint found at the base of each leaflet 

in a typical compound leaf. This absence could be 

explained by the absence of a joint at the junction of the 

leaflet and rachis in a compound-leaved ancestor, 

because Early Cretaceous taxa with pinnately compound 

leaves (such as Sapindopsis) do not appear to possess a 

joint at the junction of the leaflet and rachis (L.J. Hickey, 

oral comm., 1983; Garland Upchurch, unpublished 

observations). Although the absence of a joint in the 

leaves of Citrophyllum could reflect the evolution of the 

alate rachis through the fusion of stipules to the petiole, 

extant forms with this condition (such as many Rosaceae) 

almost always have stipules that are free from the petiole 

for part of their length. Thus, evidence favors a 

compound-leaved ancestry for Citrophyllum. 

The modern affinities of Citrophyllum appear to be 

with subclass Rosidae. Within extant angiosperms, 

compound leaves occur in Ranunculidae, Rosidae, and a 

few Dilleniidae and Asteridae (Hickey and Wolfe, 1975). 

Among these subclasses, only Rosidae has members 

where the compound leaf possesses an alate rachis (many 

Sapindaceae, some Anacardiaceae) or where there is a 

simple leaf with an alate petiole constricted at the base of 

the lamina (some Rutaceae). The general pattern of 

tertiary venation found in Citrophyllum is consistent with 

an assignment to Rosidae, because it is found in only a 

few Dilleniidae (Thymeleaceae) but characterizes many 

families of simple-leaved Rosidae, including Iteaceae, 

Olacaceae, Mastixiaceae, Rhamnaceae, Celastraceae, 

and Icacinaceae. Within Rosidae, Citrophyllum cannot be 

assigned to an extant order. This is because it has the 

alate petiole suggestive of the alate rachis in compoundleaved taxa, such as Sapindales, Rutales, and certain 

Saxifragales (for example, Cunoniaceae ), but it has the 

thin, weakly percurrent, admedially oriented tertiary 

venation characteristic of some genera in simple-leaved 

orders, such as Rhamnales, Celastrales, and Santalales. 

This combination of features today is restricted to 

separate groups of Rosidae, and thus provides fossil 

44 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
A r 

Figure 22. Dicotylophyl/um myrtophylloides new species, 15713-8303, specimen shown on 

plate 28. A, General view of specimen, x 3. 8, Enlargement of middle region, lower left leaf, x 10. 

Note the poorly organized tertiary venation. 

evidence for phylogenetic link between the simple- and 

compound-leaved families of the subclass. The occurrence of more generalized venational features in earlier 

Cretaceous compound leaves belonging to Rosidae, 

along with the apparent absence of simple-leaved Rosidae from the Early Cretaceous, provides stratigraphic 

evidence in favor of compound leaves being primitive to 

the subclass, as proposed by Hickey and Wolfe (1975). 

MAGNOLIOPSIDA subclass unknown 

Dicotylopbyllum myrtophylloides new species 

Plate 28; text figure 22 

Diagnosis.-Leaf linear. Primary venation pinnate. 

Secondary venation pinnate with an intramarginal vein; 

intramarginal vein arching between secondary veins; 

basalmost secondary vein at a lower angle than the 

superadjacent secondary veins; intercostal regions 

elongate parallel to midrib. Tertiary venation irregularly 

reticulate. 

Description.-Leaves attached to stem, phyllotaxy 

appearing to be either opposite and decussate or 

whorled; stem approximately 0.5 mm in diameter, having 

no wing of flattened tissue and hence appearing to have 

little cortical tissue. Leaves simple, linear, L/W over 7; 

lamina over 2 em long by 2-3 mm wide; apex unknown; 

base acute; petiole with a decurrent wing of laminar 

tissue; margin entire. Primary venation pinnate; primary 

vein massive, 0.3-0.4 mm wide at base of lamina. 

Secondary venation pinnate with an intramarginal vein, 

but with the intramarginal vein smoothly arching 

between secondary veins; secondary veins thin relative to 

primary vein, more than 8 pairs, with the basalmost pair 

at a lower angle than the superadjacent pairs, subopposite to alternate, irregularly spaced, diverging at 

moderate to broad acute angles, straight, connecting with 

intramarginal vein well within margin; intercostal regions 

apically elongate. Intersecondary veins present, none or 1 

per intercostal region, branching to form tertiary veins. 

Tertiary venation irregularly reticulate; tertiary veins thin 

relative to secondary veins. Higher order venation not 

preserved. 

Cuticle not preserved. 

Number of specimens examined.-! (4 leaves 

attached to one axis). 

Holotype. -15713-8303. 

Systematics 45 
Derivation of epithet.-From the genus Myrlophyllum, referring to the superficial resemblance of Dicotylophyllum myriophylloides to Myriophyllum. 

Discussion.-The one preserved specimen of 

Dicotylophyllum myriophylloides clearly represents a new 

taxon of mid-Cretaceous angiosperms. Although leaves 

of this taxon might be assigned to the genus Myriophyllum 

by some workers, D. myriophylloides differs from the type 

species of Myriophyllum (M. geinitzi) and obviously 

related forms (for example, M. angustifolium) in having 

intercostal regions that are elongate parallel, rather than 

perpendicular to, the midvein. In extant angiosperms, 

such pronounced variation in the shape of the intercostal 

regions typically segregates genera and families. (See 

table 2 for examples.) 

Leaves of D. myriophylloides resemble those of 

Myrtaceae in gross aspect, but details of secondary and 

tertiary venation preclude assignment to Myrtaceae. 

Most Myrtaceae have intercostal regions that are 

elongate at an angle to the midvein, rather than parallel 

to it, and the tertiary venation tends toward percurrent, 

rather than irregularly reticulate. Myrtaceae that have 

intercostal regions elongate parallel to the midvein, such 

as Callistemon and Rhodamnia, typically have two sets of 

associated features that are not present in D. myrlophylloides: first, the secondary veins are significantly thinner 

than the intramarginal vein and tend to intergrade with 

the tertiary veins, while the intramarginal vein is nearly 

the same thickness as the midvein and does not arch 

between the secondary veins; second, the tertiary venation is either reticulate and more highly organized than 

that of D. myriophylloides or has a strongly ramified 

component. Thus, Dicotylophyllum myriophylloides does 

not appear to represent Myrtaceae, despite a gross 

resemblance. 

The one preserved specimen of D. myriophylloides 

appears to represent four leaves attached to a slender 

axis, rather than a compound leaf. Evidence for this 

interpretation is the position and orientation of the 

laminar units in the matrix. In a compound leaf, all the 

leaflets typically are preserved on a single bedding plane, 

rather than at different levels, and petiolules are all 

oriented parallel to the bedding plane. In addition, the 

bases of the most apical pair of lateral leaflets do not 

overlap the base of the terminal leaflet. In contrast, the 

basalmost laminar unit of D. myriophylloides is located at 

a significantly higher position in the matrix than the 

superadjacent laminar units (not readily apparent on 

plate 28), and its petiole is oriented at nearly a right angle 

to the bedding plane. The superadjacent laminar units 

are orientated much more parallel to the plane of 

bedding than the most basal laminar unit; however, each 

one of these super adjacent laminar units is oriented in a 

somewhat different plane from the others, and the base 

of the medial laminar unit looks as if it is somewhat 

Figure 23. Dicotylophyllum rosafluviatilis 

new species, 15713-4698, specimen shown 

on plate 29, figures 1, 2, 4, and 5, illustrating 

secondary venation, x 1. 

obscured by the bases of the two lateral laminar units 

(pl. 28, fig. 3). The presence of a cluster of three laminar 

units at the tip of the axis implies that phyllotaxy was 

whorled. Also possible is that the leaves were arranged in 

an opposite and decussate manner and that the fourth 

leaf was preserved only on the now missing counterpart. 

Incomplete preservation of venation precludes 

assignment of D. myriophylloides to any extant order of 

angiosperms. The inferred pattern of leaf arrangement 

and details of secondary venation imply that D. myrtophylloides could be related to either Laurales (Myrlophyllum geinitzii and M. angustifolium) or Myrtales. If the 

inferred pattern of phyllotaxy is wrong, then affinities to 

Diiieniaceae (Hibbertia) are also possible (Rury and 

Dickison, 1977). Precise systematic placement awaits 

discovery of better preserved materials. 

Dicotylophyllum rosafluviatilis new species 

Plate 29; text figure 23 

Diagnosis.-Lamina ovate, but with the sides ofthe 

lamina tending toward straight-sided rather than curved; 

base cuneate; petiole distinct; margin denticulate. Primary venation pinnate, but with one pair of secondary 

veins producing exmedial branches for most of its length. 

Secondary venation craspedodromous, with each secondary vein running directly to a tooth; some secondary 

veins interconnected by an additional set of loops; basilaminar secondary veins present. Tertiary venation thin, 

subparallel, tending to be admedially oriented near the 

apex. 

46 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
Description.-Lamina ovate but with the sides of 

the lamina tending towards straight -sided rather than 

curved, L/W = 1.5 (estimated); lamina 7.5 em long 

(estimated length) by 5.2 em wide; apex probably 

attenuate (tip missing); base obtusely cuneate; distinct 

petiole present; margin denticulate and with structural 

reinforcement; teeth tending towards straight-straight 

(B-2), broad, with rounded apex, 2-3.5 mm wide by 

< 1 mm tall; sinuses broadly obtuse, rounded. Primary 

venation pinnate; primary vein moderate. Secondary 

venation simple craspedodromous, with additional brochidodromous loops connecting some adjacent secondary veins; secondary veins thick relative to the primary vein, crowded at the base of the leaf, at least 8 pairs, 

subopposite in the basal half of the lamina, alternate 

above, narrow acute; basilaminar secondary veins thin, 

unbranched, and retroflexed; second pair thicker but 

similar in behavior; third pair of secondary veins thick, 

straight, and with external branches for most of their 

length; the superadjacent secondary veins successively 

thinner and with external branches for less than half their 

length; external branches of the secondary veins always at 

a narrow acute angle to source vein. Tertiary venation 

per current; tertiary veins thin relative to secondary veins, 

arising at an acute angle on the exmedial side of the 

secondary veins and an acute to right angle on the 

admedial side, joining the primary vein at an acute to 

right-angle, convex. Quaternary venation unbranched to 

reticulate; quaternary veins thick relative to tertiary 

veins, without strong orthogonal rooting, irregular in 

spacing and course. Teeth showing no evidence of strong 

glandularity (but preservation is poor); medial vein 

symmetric; accessory venation obscure but obviously not 

strongly developed; features of teeth difficult to discern 

because of decay and the darkened remnants of the 

reinforcement tissue along the margin. 

Number of specimens examined. -1. 

Holotype.-15113-4698, 4698' (part and counterpart). 

Derivation of epithet.-Latin, rosa =rose, 

fluviatilis =of a stream, referring to the occurrence of 

this species at the Rose Creek locality. 

Discussion.-Dicotylophyllum rosafluviatilis represents a distinct taxon of mid-Cretaceous angiosperm 

foliage. If the teeth and higher order venation were better 

preserved, the specimen probably would be the basis for 

a new genus. However, because poor preservation makes 

confident assignment to a subclass impossible, we have 

assigned the specimen to Dicotylophyllum. Among previously described species of mid-Cretaceous angiosperm 

foliage, D. rosafluviatilis most closely resembles "Grataegus" lacoei? Lesquereux (1892, pl. 64, fig. 14; pl. 66, fig. 

2) and "Viburnum" lesquereuxii Ward var.longifolium (in 

Lesquereux, 1892, pl. 53, fig. 1) in shape and pattern of 

secondary venation. D. rosafluviatilis differs from "C." 

Figure 24. Dicotylophyllum aliquantuliserratum new species, 15713-4707, specimen 

shown on plate 30, figure 2, details of brochidodromous looping and margin, x 5. 

lacoei? in having a distinct petiole and from "V." 

lesquereuxii var. longifolium in having more closely 

spaced tertiary veins that tend to be admedially oriented 

in the apical part of the lamina. The unusual pattern of 

secondary venation shared by these three species implies 

that they are possibly congeneric, but confirmation of this 

suggestion awaits study of better preserved materials. 

The general pattern of secondary venation found in 

Dicotylophyllum rosafluviatilis occurs in many families of 

dicotyledons but is most characteristic of subclass 

Hamamelididae. The exact pattern of secondary venation 

found in D. rosafluviatilis (with a pair of basilaminar 

secondary veins, a superadjacent pair of recurved, 

sparsely branched secondary veins, and a third pair of 

craspedodromous secondary veins that are branched for 

most of their length) has only been observed in Eupteleaceae. Although this could indicate a relationship 

between D. rosafluviatilis and Eupteleaceae, tooth 

structure is not well enough preserved in D. rosafluviatilis 

to determine affinities. Further, Eupteleaceae differ 

from D. rosafluviatilis in having a margin without 

structural reinforcement, larger teeth, less branched and 

more regular tertiary venation, and quaternary venation 

that encloses quadrangular regions of fairly regular size 

and shape. Thus, Dicotylophyllum rosafluviatilis may 

belong to Hamamelididae, but better preserved specimens are needed to accurately determine modern 

affinities. 

Dicotylophyllum aliquantuliserratum new species 

Plate 30; text figure 24 

Diagnosis.-Lamina narrow elliptic, margin with 

minute serrations that are generally visible only with 

magnification. Primary venation pinnate. Secondary 

Systematics 47 
venation festooned brochidodromous; secondary veins 

numerous, closely spaced, moderate to broad acute; 

brochidodromous junction formed by secondary veins of 

equal thickness, with the superadjacent vein deflected 

apically; each secondary vein forming an apically arching 

series of excostal loops. Tertiary veins admedially 

oriented. 

Description.-Lamina elliptic, L/W over 3; lamina 

at least 4.5-5.5 em long by 1.4-1.8 em wide; apex acute 

and tending toward rounded at the tip; base missing; 

margin minutely serrate. Primary venation pinnate; primaryvein stout. Secondary venation festooned brochidodromous; secondary veins thin relative to the primary vein, 

numerous, closely but somewhat irregularly spaced, 

slightly decurrent, moderate to broad acute, with only a 

few of the secondary veins showing significant differences 

in divergence angle; course somewhat irregular, not 

curving apically until looping, forming loops at irregular 

distances from the margin; brochidodromous junction 

formed by secondary veins of equal thickness, the superadjacent secondary vein deflected apically; angle ofbrochidodromous junction acute to obtuse; each. secondary 

vein gradually thinning and forming its own series of 

irregularly proportioned excostal loops that run to near 

the margin; excostal loops tending towards curved on 

their exmedial sides. Intersecondary veins occasionally 

present. Tertiary venation generally obscure, probably 

reticulate; tertiary veins (when preserved) forming an 

acute or right angle on the exmedial side of the secondary 

veins and an obtuse or right angle on the admedial side, 

oriented towards midvein. Discontinuities present in the 

lamina of one specimen, appearing to represent venation, 

if so, then higher order venation irregularly reticulate. 

Cuticle not preserved. 

Number of specimens examined.-5. 

Holotype.-15113-4811A, 4877B. 

Paratypes.-15113-4104, 7804. 

Derivation of epithet.-Latin, aliquatulus =small, 

and serra =saw, referring to the small teeth that often 

can be seen only under the microscope. 

Discussion.-These remains, though preserved as 

fragments, resemble leaflets of an entire-margined, pinnately compound leaf type from the Potomac Group of 

Maryland that was informally included within the genus 

Sapindopsis Fontaine by Doyle and Hickey (1976, 

figs. 23, 24), Hickey and Doyle (1977), and Upchurch 

(1984). Similarities include a narrow elliptic shape, stout 

primary vein, numerous secondary veins (each forming 

its own series of irregular excostalloops that extends to 

near the margin), excostalloops that are curved on their 

outer sides, and reticulate tertiary venation where the 

tertiary veins originate at acute to right angles on the 

exmedial sides of the secondary veins and right to obtuse 

angles on the admedial side. The Rose Creek fossils 

compare favorably with the Potomac Group leaves in 

other preserved features except for the minutely serrate 

margin, which is unknown in any of the leaves assigned to 

Sapindopsis. The Rose Creek fossils show points of 

similarity with "Hymenaea" dakotana Lesquereux from 

the Dakota Formation of Kansas (Lesquereux, 1892, pl. 

55, figs. 2, 3; pl. 56, figs. 1, 2; pl. 62, fig. 2) but differ in 

their denticulate margin, less regular secondary venation, 

and less admedially oriented tertiary venation. D. aliquantuliserratum also resembles remains from the 

Cheyenne Sandstone of Kansas (improperly) assigned by 

Berry to Sapindopsis variabilis Fontaine and S. magnifolia Fontaine (Berry, 1922, p. 213-215, pl. 55, figs. 2-5; pl. 

56, figs. 1-3), particularly in shape and secondary venation, but it differs in the character of its margin. Finally, 

D. aliquantuliserratum resembles various serrate leaf 

types that have pinnatifid and pinnately compound 

organization, such as Sapindopsis belvederensis Berry 

(1922) and Anarcardites neuburgae Vakhrameev (1952), 

in general pattern of secondary venation but differ in the 

details of the margin. These similarities are such that if 

the Rose Creek fossils were preserved as leaflets or lobes 

pinnately arranged along a rachis we would describe 

them as a new species of Sapindopsis. However, in the 

absence of better preserved materials, this leaf type is 

assigned to the form genus Dicotylophyllum. 

Dicotylophyllum expansolobum new species 

Plate 31; text figure 25 

Diagonosis.-Leaf simple, five-lobed; lobes all 

diverging at approximately the same level on the leaf; 

each lobe widest above the base; margin with minute 

teeth that are difficult to see without magnification. 

Primary venation basally palmate; primary veins 5, stout/ 

masstve. 

Description.-Leaf simple, five-lobed; lamina over 

8.5 em long by over 7.5 em wide; lobes 0.4-0.8 em wide at 

base, with a maximum width of3.0 em (estimated); apex 

of lobes missing; sinuses between lobes rounded; base of 

lamina obtusely cuneate; margin with both structural 

reinforcement and minute serrations; serrations ranging 

from concave to straight on the apical side and straight to 

convex on the basal side, less than 1 mm wide by less than 

0.3 mm tall; distinct petiole present, over 1 em long. 

Primary venation palmate, exact pattern difficult to 

discern because of poor preservation; primary veins stout 

or massive, 1 mm wide at base of leaf, with a straight 

course. Secondary and higher order venation obscure 

due to poor preservation; one secondary vein observed, 

thin, less than 0.2 mm wide. 

part). 

Cuticle badly fragmented, no preparations made. 

Number of specimens obse!Ved.-1. 

Holotype.-15113-8304, 8304' (part and counter48 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
/!,, :-; / ...... __ ~-- ' - ,, / .... \ \ 

'l ( \1 } ,'1 ... "") I 1 1 I (- _ _, ( 

\\1 ...J I\. \ 

._... r ' ' ' l ', ('- \ 

' I "' ..... _ -.... I ' ... --... ... ------- rj ,. 

A 

I '\ 

'/ \ 

\ ... , \ 

r ".) I ,' .. ·. · .. I • • • • • 

\ ... I 

I 

. .. • • • I. 

B

·::': .. : 

.. 

Figure 25. Dicotylophyllum expanso/obum new species. A, 15713-8304' (counterpart), 

specimen shown on plate 31, figure 1, x 1. 8, 15713-8304 (part), specimen shown on plate 31, 

figures 2--4, teeth along the margin of two adjacent lobes, x 7.5. Areas of leaf tissue are 

stippled. 

Derivation of epithet.-Latin, expansus= spread 

out, and lobus= lobe, referring to the expansion of the 

lobes above their base. 

Discussion.-Dicotylophyllum expansolobum is 

clearly distinct from any previously described type of 

Cretaceous leaf, despite poor preservation. The surficial 

wrinkling and evidence for a structurally reinforced 

margin imply that this leaf was thick-textured in life. The 

primary veins of this leaf possess longitudinal striations, 

which were originally interpreted as evidence of a multistranded primary vein. However, the strong wrinkling 

found on other parts of the leaf indicate that this 

probably is an artifact of preservation. 

Among previously described species of fossil angiosperms, Dicotylophyllum expansolobum most closely 

resembles several species of lobed leaves of Cenomanian 

age. These include ''Aralia" quinquepartita Lesquereux 

(1871, p. 302; 1874, pl. 15, fig. 6) and "Sterculia" lugubris 

Lesquereux (1883, pl. 6, figs. 1-3), both from the Dakota 

Formation of Kansas. Similarities shared by these three 

taxa include palmate organization and similar shape to 

the lobes, sinuses, and laminar base. However, Dicotlyophyllum expansolobum differs from ''A." quinquepartita in 

having small teeth and in having the sinuses between the 

inner and outer pairs of lobes occur at approximately the 

same level on the leaf, rather than at different levels; D. 

expansolobum differs from "S ." lugubris in having small 

teeth and five lobes. Unfortunately, none of these species 

preserves venation above the first order well, precluding 

closer comparison. 

The modern affinities of Dicotlyophyllum expansolobum are uncertain because of poor preservation. No 

extant species of Magnoliidae has pentalobate organization with basally palmate primary venation. 

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52 Rose Creek Locality, Jefferson County, Southeastern Nebraska 
INDEX 

[Italic page numbers indicate major references] 

A Page 

Abaxial, defined ............................................... 3 

Abstract. ............................................................ l 

Abmedial, defined ........................................... 2 

Acerites ............................................................ 23 

ftcifolia .................................................... 23 

multifonnis ....................................... 21, 24 

Acritodromum, new genus .................... 36, 37 

ellipticum .............. 7, 9, 11, 36, 37; pl. 23 

Adaxial, defined ............................................... 3 

Admedial, defined ........................................... 2 

Age ............................................................... 5, 6 

aligerum, Citrophyllum ..................... .43; pl. 27 

aliquantulisen'antum, Dicotylophyllum .. 7, 10, 

11, 47; pl. 30 

Amborella trichopoda ................................. pl. 7 

Amborellaceae ......... 7, 8, 20, 21, 23, 25, 41; 

pl. 7 

Anacardiaceae ................................................ 44 

Anarcardites neuburgae ................................ .48 

"Andromeda" latifolia .................................. .43 

paralatorii ................................................ 27 

Angiosperm classification .............................. ! 

angularis, Dicotylophyllum .... 7, 11, 40; pl. 25 

Anisodromum, new genus ...................... 42, 44 

wolfei.. ............ 7, 9, 11, 42, 43, 44; pl. 26 

Annonaceae ................................... 7, 13; pl. 2 

Appendicisporites .............................................. 6 

Appolonias canariensis ............................. pl. 10 

Aquifoliaceae ........................................... 27, 38 

''Aralia" quinquepartita ................................. 49 

Araliaceae ....................................................... 24 

Araliaephyllum ................................................ 23 

obtusilobum ............................................ 23 

Areolation ......................................................... 3 

Archaeanthus ..................................................... 8 

Ascarina ........................................................... 16 

philippensis .......................................... pl. 7 

Aspen Shale, Wyoming ................................ 24 

Asteridae .................................................. 43, 44 

Atherospermataceae ..... 23, 25, 28; pls. 9, 10 

Atlantic Coastal Plain, Zone III .................. 6 

attenuatum, Pandemophyllum 7, 11, 29; 

pls. 13, 16 

Austrobaileya scandens ............................. pl. 7 

Austrobaileyaceae ........ 8, 20, 21, 25, 36, 40; 

pl. 7 

B 

Basinger, James ............................................ 35 

basingerii, Didromophyllum 7, 9, 10, 34, 35; 

pls. 21, 22 

Berchemia ................................................... 9, 43 

Bhesa ........................................................... 9, 43 

Brachidontes bivalves ....................................... 6 

Brackish-water facies ...................................... 9 

Bubbia argentea .......................................... pl. 2 

sp ......................................................... pl. 2 

c Page 

Callistemon ..................................................... 46 

calophylla, Landonia ....... 7, 8, 12, 18, 19, 20, 

41; pl. 6 

Canellaceae ....................................... 18, 20, 37 

Capsicodendron .............................................. 20 

Celastraceae ............................................. 43, 44 

Celastrales ................................................ 43, 44 

Celastrophyllum ................................. 16, 17, 32 

angustifolium .......................................... 16 

attenuatum .............................................. 14 

crenatum .................................... 16, 38, 39 

decu"ens ........................................... 13, 14 

hunteri ...................................................... 15 

latifolium ................................................. 17 

obovatum ................................................ 17 

undulatum ........................................ 38, 39 

Celastraceae ............................................... 9, 14 

Celastrales ........................................................ 9 

Celastrus .......................................................... 15 

"Celastrus" arctica .......................................... 33 

Cenomanian age .............................................. 6 

cf., defined ........................................................ 7 

Cheiropleuriaceae ......................................... 35 

Cheyenne Sandstone ............................... .4, 48 

Chloranthaceae ....... 7, 8, 16, 17, 18, 40; pl. 7 

Chloranthus .............................................. 16, 40 

Cinnamodendron ............................................ 18 

"Cinnamomum" linifolium ........................... 24 

Citrus ................................................................ 44 

Citrophyllum ............................................. 43, 44 

aligerum ...................................... 43; pl. 27 

doylei.. ................... 7, 9, 11, 43, 44; pl. 27 

Classification, angiosperms ............................ ! 

criteria .............................................. 3, 4, 7 

Takhtajan .................................................. 7 

Classopollis ....................................................... 6 

Cloud County, Kansas, Pipe Creek ............ 38 

Cocculophyllum ......................................... 8, 24 

Comparisons, extant taxa ......... 16, 21, 25, 27 

confere, defined ............................................... 7 

Congeneric species ......................................... .4 

Convergent morphologies .............................. 3 

Comales ..................................................... 9, 43 

Coula ........................................................... 9, 43 

Crassidenticulum, new genus ....................... 13 

dec~ens ....... 7, 8, 10, 13, 16, 17, 18, 38, 

40; pls. 3, 4 

extant taxa comparison ........................ 16 

"Crataegus" lacoei? ........................................ 47 

Cunoniaceae ................................................... 44 

Cuticle anatomy ............................................. 23 

Dicotylophyllum angularis .................... .40 

Illicium florid anum .......................... pl. 20 

parvijlornm ................................ pl. 20 

temstroemoides ......................... pl. 20 

Kadsura japonica ............................. pl. 20 

oblongifolia ............................... pl. 20 

phillipensis ................................. pl. 20 

Cuticle anatomy-Continued Page 

Longstrethia varidentata ... 32; pls. 19, 20 

Nectandra tarascensis ....................... pl. 17 

Ocotea bracteata ............................... pl. 17 

tristis ........................................... pl. 17 

Pabiana variloba ....................... 22; pl. 11 

Pandemophyllum attenuatum .. 29; pl. 16 

kvacekii ............................... 26; pl. 15 

sp ................................ .30; pls. 16, 17 

Sassafras albidum ............................ pl. 11 

Staudtia gabonensis .......................... pl. 17 

Cuticle preparation ......................................... 3 

Cuticular terminology ..................................... 3 

D 

Dakota Formation, Kansas ...... .4, 13, 30, 43, 

48, 49; pl. 14 

Daphnogene .................................................... 28 

cinnamomeifolia ..................................... 28 

Daphniphyllum ............................................... 28 

Daphnophyllum ........................................ 27, 28 

crassinerve ............................................... 28 

decurrens, Crassidenticulum .. 7, 8, 10, 13, 16, 

17, 18, 38, 40; pis. 3, 4 

Degeneria vitiensis ....................................... pl. 2 

Degeneriaceae .......................... 7, 13, 36; pl. 2 

Densinervum, new genus .............................. 17 

extant taxa comparison .................. 16, 18 

kaulii ............................ 7, 11, 17, 18; pl. 5 

Deposited materials ........................................ 2 

Depositional environment ......................... 6, 9 

Dicotylophyllum ................. 4, 7, 40, 45, 47, 48 

aliquantulisen'antum ........... 7, 10, 11, 47; 

pl. 30 

angularis ........................... 7, 11, 40; pl. 25 

expansolobum .................. 7, 10, 48; pl. 31 

generic term ............................................. 4 

myrtophylloides ................ 7, 11, 45; pl. 28 

rosajluviatilis ................... 7, 10, 46; pl. 29 

Didromophyllum, new genus ................ .34, 36 

basingerii... .... 7, 9, 10, 34, 35; pls. 21, 22 

Dilleniaceae .................................................... 46 

Dilleniidae ........................................... 3, 43, 44 

"Diospyros "pseudoanceps ............................. 27 

Dipteridaceae ................................................. 35 

Doyle, James A ............................................. 44 

doylei, Citrophyllum ..... 7, 9, 11, 43, 44; pl. 27 

Drimys dictyophlebia .................................. pl. 2 

E 

Ebenaceae ....................................................... 27 

Ecological considerations .......................... 6, 9 

"Elaeodendron" speciosum ..................... pl. 25 

ellipticum, Acritodromum ..... 7, 9, 11, 36, 37; 

pl. 23 

Em1notum ....................................................... 43 

Ephippiandra .................................................. 20 

Index 53 
Page Page 

Ericaceae ......................................................... 27 Hedycarya denticulata ................................ pl. 7 

Escalloniaceae ................................................ 43 Hedyosmum .................................................... 16 

Eucalyptophyllum .................................... 32, 41 arborescens .......................................... pl. 7 

Eucalyptus ....................................................... 32 Hemandiaceae .................... 7, 8, 21, 25; pl. 10 

"Eucalyptus" angustifolia .............................. 33 Hibbertia .......................................................... 46 

dakotensis ................................................ 33 Hickey publications ........................................ .3 

geinitzi ...................................................... 33 Honorees, Basinger, James ......................... 35 

Euphorbiaceae ................................................. 3 Doyle, James A ................................... .44 

Eupomatiaceae ................................................. 7 Kaul, Robert B ..................................... 17 

Eupteleaceae .................................................. 47 Kvacek, Dr. Zlatko .............................. 27 

Eusidereroxylon ............................................... 28 l.,andon, James ..................................... 19 

zwageri ............................................... pl. 10 Longstreth, Karl ................................... 31 

Evolutionary trends .................................... 2, 8 Pabian, Roger ....................................... 21 

Examination methods ..................................... 2 Reynolds, Howard .............................. .37 

Exmedial, defined ............................................ 2 Rose Creek ........................................... 47 

expaJZSolobum, Dicotylophyllum ....... 7, 10, 48; Wolfe, Jack A ....................................... 42 

pl. 31 Hortonia angustifolia ................................ pl. 10 

Extant taxon, comparison .............................. 7 Hortoniaceae ..................................... 25; pl. 10 

Ansiodromum ......................................... 43 "Hymenaea" dakotana ........................... .42, 48 

Citrophyllum ........................................... 44 

Crassidenticulum .................................... 16 

Densinervum ........................................... 16 

Dicotylophyllum myrtophylloides ......... .46 

Landonia ................................................. 21 

uurales .................................. pls. 7, 9, 10 

Magnoliales ........................................ pl. 2 

Pabiania .................................................. 25 

Icacinaceae ............................................... 43, 44 

Idiospermaceae ...................... 23, 25, 37; pl. 7 

Idiospennum australiense .......................... pl. 7 

/lex dipyrena .................................................... 38 

masonii .................................................... 37 

Pandemophyllum ................ 25, 27; pl. 14 "/lex" scudderi ................................................ 27 

Reynoldsiophyllum ................................ .40 Illiciales ............................................ 8, 9, 30, 40 

F 

extant taxa ........................... 33, 34; pl. 20 

Illicium ............................................................ 33 

floridanum ......................................... pl. 20 

Ficophyllum .................................................... 36 parviflornm ........................................ pl. 20 

tenuinen>e ................................................ 13 temstroemoides .................................. pl. 20 

Ficus aligera .................................................... 43 Illigera ................................................................ 8 

"Ficus" inaequalis .......................................... 27 

1nacrophylla ........................................ 8, 13 

vespertilla ........................................... pl. 10 

"lnga" cretacea ................................... 30; pl. 14 

virginiensis ............................................... 13 Iteaceae .................................................... 43, 44 

Ficophyllum ................................................ 8, 36 

crassinen>e ............................................... 13 J 

Floristic composition ...................................... 7 

Florida Museum of Natural History ............ 2 

Fluvial conditions ............................................ 6 

Foliar architecture ........................................... 2 

Janssen Clay Member ............................... 5, 6 

"Juglans" debeyana ........................................ 12 

F ontainea ......................................................... 35 

Formations ................................................... 4, 5 K 

See also Rock units. 

Kadsura ........................................................... 33 

G japonica ............................................. pl. 20 

oblongifolia ....................................... pl. 20 

Generic level taxon ........................................ .4 phillipensis ......................................... pl. 20 

Gilbertia ........................................................... 24 Kansas, Pipe Creek ...................................... .38 

Gleicheniidites ................................................... 6 Kaul, Robert B .............................................. 17 

Gomortega keule ............................ 20; pis. 6, 7 

Gomortegaceae ................ 7, 8, 20, 21, 23, 25; 

pis. 6, 7 

Graneros sea .................................................... 6 

kaulii, Densinervum ............ 7, 11, 17, 18; pl. 5 

Kvacek, Dr. Zlatko ....................................... 25 

kvacekii, Pandemophyllum ....... 7, 11, 26, 37; 

pis. 12, 13, 15 

Greenhorn transgression .............................. .4 

Greenland, Patoot flora ............................... 38 L 

Gyrocarpaceae ............................ 23, 25; pl. 10 

l.,andon, James ............................................... 19 

H Landonia, new genus .................................... 18 

calophylla ... 7, 8, 12, 18, 19, 20, 41; pl. 6 

Haliserites ........................................................ 35 extant taxa comparison ........................ 21 

Hamamelididae .............................................. 47 uuraceae .... 8, 23, 25, 27, 28; pis. 10, 11, 17 

54 Rose Creek Locality, Jefferson County, Southeastern Nebraska 

Page 

l.,aurales ................ 7, 8, 13, 16, 20, 23, 24, 25, 

26, 28, 33, 35, 36, 37, 

41, 46; pis. 9, 10 

Laurophyllum ......................................... 27, 28 

kujianum ................................................ 28 

Laurus plutonia .............................................. 27 

Leguminosae .................................................. 27 

Leguminosites hymenophyllus ...................... .42 

Lindera .................................................. 23; pl. 9 

"Lindera" venusta .......................................... 24 

Liriophyllum ........................................ 8, 35, 36 

Litsaeophyllum ............................................... 28 

wingellense .............................................. 28 

Longstreth, Karl ............................................ 31 

Longstrethia, new genus ............................ 9, 30 

varidentata ............... 7, 10, 11, 30, 31, 32, 

33, 34; pis. 18, 19, 20 

Locality, defined ............................................. 5 

M 

"Magnolia" pseudo-acuminata ..................... 27 

Magnoliaceae ....................................... 36; pl. 2 

Magnoliales ..................................... 8, 36; pl. 2 

Magnoliid-grade foliage ...................... 7, 8, 34 

Magnoliidae ........ 1, 4, 7, 8, 9, 12, 13, 16, 18, 

20, 24, 27, 28, 33, 34, 

35, 36, 37,40,41,49 

Magnoliopsida ................................................ 45 

Malden Mountain assemblage ...................... 8 

Manglietia fordiana .................................... pl. 2 

hookeri ................................................. pl. 2 

masonii, Reynoldsiophyllum .......... 37, 38, 39; 

pl. 23 

Mastixiaceae ................................................... 44 

Mollusks, Brachidontes ................................. 10 

Monimiaceae ........... 7, 8, 20, 21, 25, 41; pl. 7 

Moraceae ........................................................ 27 

"Myrica" aspera ........................................ 38, 39 

zenkeri ...................................................... 15 

Myristicaceae ............................... 28, 37; pl. 17 

Myrtales .................................................... 32, 46 

Myrtaceae ....................................................... 46 

myrtophylloides, Dicotylophyllum .......... 7, 11, 

45; pl. 28 

Myrtophyllum .............................. 28, 32, 41, 46 

angustifolium ................................... 32, 46 

geinitzii ........................... 32, 33, 46; pl. 14 

warderi ..................................................... 33 

"Myrtophyllum" tmreyi ................................... 15 

N 

nebrascense, Reynoldsiophyllum.7, 10, 39, 40; 

pl. 24 

Nectandra tarascensis ............................... pl. 17 

New genera, explained ................................... .4 

New genus A .................. 7, 8, 11, 12, 13; pl. 1 

New genus B ....................... 7, 9, 11, 41; pl. 25 

0 

Ocotea bracteata ....................................... pl. 17 

tristis ................................................... pl. 17 

Olacaceae ............................................. 9, 43, 44 
p Page 

Pabian, Roger ................................................ 21 

Pabiania, new genus ................... 21, 37; pl. 10 

extant taxa comparison ........................ 25 

variloba ......... 7, 8, 11, 21, 23, 24, 25, 37; 

pis. 8, 9, 11 

Paleoenvironments ............................... 6, 9, 10 

Pandemophyllum, new genus ...... 7, 8, 11, 22, 

26, 27, 28, 29, 30, 37; 

pis. 10, 14, 16, 17 

attenuatum ............. 7, 11, 29; pis. 13, 16 

extant taxa comparison ......... 25; pis. 10, 

11, 14, 17 

kvacekii.. ..... 7, 11, 26, 37; pis. 12, 13, 15 

sp ...................... 7, 11, 30; pis. 14, 16, 17 

Patoot flora, Greenland ............................... 38 

Phaseolites fonnus .......................................... 27 

Phyllanthoideae ................................................ 3 

Picture matching .............................................. 1 

Pipe Creek, Cloud County, Kansas ............ 38 

Piperales ............................................................ 7 

Piptocalyx ........................................................ 16 

Potomac Group ...................................... 13, 17 

Maryland ........................................... 8, 48 

Virginia ................................................... 32 

Proteaephyllum ovatum ................................. 13 

Proteoides daphnogenoides ............... 30; pl. 14 

Proteophyllum .......................................... 28, 32 

bipinnatum .............................................. 28 

laminarium ............................................. 28 

Pyritic nodules ................................................. 6 

Q 

Quaternary, defined ........................................ 2 

Quatary, defined .............................................. 2 

Quercophyllum ................................................ 15 

grossidentatum ......................................... 5 

tenuinerve ................................................ 20 

Quinternary, defined ....................................... 2 

Quintary, defined ............................................ 2 

R 

Ranunculidae ................................................. 43 

Raritan Formation ........................... 33, 38, 43 

Red Branch Member, Woodbine 

Formation .................... 6 

References cited ............................................ 49 

Reynolds, Howard ......................................... 37 

Reynoldsiophyllum, new genus .............. 37, 38 

masonii .......................... 37, 38, 39; pl. 23 

nebrascense ................ 7, 10, 39, 40; pl. 24 

Rhamnaceae ........................................ 9, 43, 44 

Page 

Rhamnales ........................................... 9, 43, 44 

Rhamnidium ....................... ....................... 9, 43 

Rhamnus ......................................................... 43 

"Rhamnus" pnmifolius .................................. 43 

Rhodamnia ...................................................... 46 

"Rhus" powelliana ......................................... 42 

uddeni .......................................................... 42 

Rock units .................................................... 4, 5 

Amboy clays, New Jersey .................... 16 

Aspen Shale, Wyoming ........................ 24 

Cheyenne Sandstone ....................... .4, 48 

Dakota Formation ........................... .4, 43 

Kansas ............ 13, 30, 48, 49; pl. 14 

Dakota Group ....................................... 33 

Graneros Formation .............................. .4 

Greenhorn Formation ........................... .4 

Patoot.flora, Greenland ....................... 38 

Potomac Group ..................................... 13 

Maryland ...................................... 8, 48 

Virginia ...................................... 15, 32 

Zone 1 ............................................... 17 

Raritan Formation .................. .33, 38, 43 

Terra Cotta Clay .................................... 5 

Upper Cretaceous, 

Czechoslovakia ................... 24, 28 

Woodbine Formation ................. 6; pl. 14 

Rogersia .............................................. 32, 37, 41 

?Rogersia denticulata ..................................... 16 

Root, fossil plant.. ............... 1, 6, 7, 10; pl. 24 

rosafluviatilis, Dicotylophyllum ....... 7, 10, 46; 

pl. 29 

Rosales ............................................................ 43 

Rosidae .......................... 3, 7, 9, 42, 43, 44, 45 

Rugubivesiculites rugosus ................................ 6 

Rutaceae ......................................................... 44 

Rutales ................................................. 9, 43, 44 

s 

Sageraea laurifolia ...................................... pl. 2 

Salicaceae ........................................................ 27 

Saliciphyllum .................................................. 37 

"Salix" deleta ............................... 21, 30; pl. 14 

newberryana ............................................ 16 

Santalales ................................................. 43, 44 

Sapindaceae .................................................... 44 

Sapindales .................................................. 9, 43 

Sapindopsis .................................... 9, 42, 44, 48 

belvederensis ............................................ 48 

magnifolia ............................................... 48 

variabilis .................................................. 48 

"Sapindopsis" elliptica ..................... 32, 33, 37 

Sarcandra .................................................. 16, 40 

Sassafras .......................................................... 23 

albidum ................................. pls. 9, 10, 11 

"Sassafras" acutilobum ................................. 24 

bilobatum ........................................ 24, 35 

i:rU.S. GOVERNMENT PRINTING OFFICE: 199Q-773-047106,063 REGION NO. 8 

"Sassafras"- Continued Page 

bradleyi .................................................... 24 

potomacensis ........................................... 24 

progenitor ................................................. 24 

Saxifragales .............................................. 43, 44 

Schisandra prop in qua .................................... 33 

Schisandraceae ......................................... pl. 20 

Siparuna decipiens ............................. pis. 9, 10 

Sparattanthelium tupiniquinorum ........... pl. 10 

Staudtia gabonensis .................................. pl. 17 

"Sterculia" snowii var. disjuncta .... 35; pl. 22 

lugubris .................................................... 49 

Subzone II-b .................................................... 6 

T 

Takhtajan, classification ................................. 7 

Terminology, confere ...................................... 7 

cuticular .................................................... 3 

venation .................................................... 3 

Terminology defined .................................. 2, 3 

Terra Cotta Clay ............................................. 5 

Theaceae ......................................................... 20 

Thymeleaceae ................................................. 44 

Tidal amplitudes ............................................ 10 

Tricolpites sag ax ............................................... 6 

Tricolporopollenites aliquantulus .................... 6 

Trimenia .......................................................... 16 

weinmanniae ....................................... pl. 7 

Trimeniaceae ............... 7, 16, 23, 33, 34; pl. 7 

v,w 

varidentata, Longstrethia ..... 7, 10, 11, 30, 31, 

32, 33, 34; pis. 18, 19, 20 

variloba, Pabiania ...... 7, 8, 11, 21, 23, 24, 25, 

37; pis. 8, 9, 11 

Venation terminology ..................................... 3 

"Viburnum" lesquereuxii var. longifolium .. .41 

Winteraceae ........ ?, 8, 9, 13, 36, 37, 44; pl. 2 

Wolfe, Jack A ................................................ 42 

wolfei, Anisodromum ...... 7, 9, 11, 42, 43, 44; 

pl. 26 

Woodbine Formation ............................. pl. 14 

Red Branch Member .............................. 6 

Word usage ...................................................... 3 

X,Z 

Xeromorphic foliage ..................................... 10 

Zone, sub, II-b ................................................ 6 

Zone III, Atlantic Coastal Plain .................. 6 

Zygogynum ...................................................... 13 

balansae ............................................... pl. 2 

Index 55 

PLATES 1-31 

[Contact photographs of the plates in this report are available, at cost, from the U.S. Geological Survey 

Photographic Library, Federal Center, Denver, Colorado 80225.] 
PLATE 1 

Figures 1-4. New genus A, 15713-4879A (p. 12) 

1. General view, x 1. 

2. Middle portion of leaf, showing origin of secondary veins, x 2. 

3. Left side of leaf, showing the slightly sinuate margin with structural reinforcement (dark area), x 10. 

4. Lower portion of leaf, showing the multistranded midrib, reticulate tertiary venation, and numerous 

laminar resin bodies to the left of the midvein, x 10. 
U S GEOLOGICAL SURVEY BULLETIN 191 5 PLATE 1 

NEW GENUS A 
PLATE2 

(All figures x 1 except where indicated] 

Figures 1-8. Foliage of select extant Magnoliales 

1. Manglietia hooken (Magnoliaceae). U.S.G.S. Ref. Coli. no. 1144a. 

2. Manglietia fordiana Oliv. (Magnoliaceae). U.S.G.S. Ref. Coil. no. 1067a. 

3. Bubbia aff. argentea A.C. Smith (Winteraceae). U.S.G.S. Ref. Coli. no. 8889. 

4. Drimys cf. dictyophlebia Diels (Winteraceae). U.S.G.S. Ref. Coil. no. 7847. 

5. Zygogynum balansae v. Tiegh. (Winteraceae), basal half of leaf. U.S.G.S. Ref. Coli. no. 2314b. 

6. Sageraea laurifolia (Annonaceae). U.S.G.S. Ref. Coli. no. 3927. 

7. Degeneria vitiensis Bailey & A.C. Smith (Degeneriaceae). U.S.G.S. Ref. Coli. no. 750. 

8. Bubbia sp. (Winteraceae), closeup of venation. USNM Cleared Leaf no. 237, x 5. 
U.S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 2 

EXTANT MAGNOLIALES 
PLATE 3 

[All figures x 1 except where indicated] 

Figures 1-8. Crassidenticulum decwrens (Lesquereux) new combination (p. 13) 

1-3. 15713-4730. 

1. General view of fragment preserving basal portion of a leaf. 

2. Enlargement of figure 1 showing the thin, apically curved secondary venation, x 2. 

3. Enlargement of figure 2 showing a secondary vein terminating in a tooth (arrow) and the 

structural reinforcement of the margin (dark regions along edge of leaf), X 5. 

4, 7. 15713-4746. 

4. General view of specimen preserving apical portion of leaf, x 2. 

7. Enlargement of figure 4 showing well-developed brochidodromous looping of the secondary 

veins, x5. 

5. 15713-4723. Specimen showing decurrent laminar base and flaring of the base immediately above 

petiolar region, x 2. 

6. 15713-7818. Specimen showing entire margin. 

8. 15713-7817. Specimen preserving the basal two-thirds of lamina. 
U.S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 3 

CRASSIDENTICULUM DECURRENS (LESQUEREUX) NEW COMBINATION 
PLATE 4 

[All figures x 1 except where indicated) 

Figures 1-6. Crassidenticulum decU1rens (Lesquereux) new combination (p. 13) 

1. UKSM 7257. Holotype. 

2. 15713-4732'. Specimen presetving basal half of lamina and numerous leaf mines in top half. 

3. 15713-4728. Specimen presetving large dark circular galls, x 2. 

4. 15713-4938. Specimen with crenate margin showing structural reinforcement along entire length of each 

tooth, x5. 

5. 15713-4795A. Closeup of multistranded midvein and decurrent secondary veins, x 10. 

6. 15713-4746. Enlargement of lower right-hand region of specimen illustrated on plate 2, figure 4. Note the 

intersecondary vein (arrow) and poorly organized tertiary and quaternary venation, x 10. 
U S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 4 

4 

6 

CRASSIDENTICULUM DECURRENS (LESQUEREUX) NEW COMBINATION 
PLATE 5 

[All figures x 1 except where indicated) 

Figures 1-6. Densinervum kaulii new species (p. 17) 

1. 175713-4841A'. Specimen showing indentation of the lamina above the widest part (arrow). 

2. 15713-7815. Specimen showing petiolar region with wing of laminar tissue along right side (arrow), x 7. 

3. 15713-4800A. Specimen showing ovate shape and closely spaced secondary veins, x 2. 

4. 15713-4830. Specimen showing secondary veins (arrows) and weak, irregular higher order venation, 

X 10. 

5, 6. 15713-4841A. 

5. Basal part of specimen showing closely spaced secondary veins, exmedially elongate brochidodromous loops near margin, and reticulate tertiary venation (bottom of specimen), x 5. 

6. Enlargement of figure 5, showing flattened brochidodromous arches by margin and structural 

reinforcement of margin (darkened region), x 10. 
U.S. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 5 

4 

DENSINERVUM KA ULII NEW SPECIES 
PLATE 6 

Figure 1. Gomortega keule (Mol.) Baill. (Gomortegaceae), U.S.G.S. Ref. Coil. no. 2462, x2. Note irregularly transverse tertiary 

venation with admedially ramified lateral branches. 

2-5. Landonia calophylla new species (p. 19) 

2. 15713-4881A', counterpart showing elongate petiolar region, x 1. 

3-5. 15713-4881A. 

3. General view of specimen showing secondary and tertiary venation, x 2. 

4. Closeup of midrib showing multistranded nature, x 7.5. 

5. Closeup of thick secondary vein at its origin. Note short exmedial branch of the secondary vein 

(arrow), x 10. 
U S. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 6 

GOMORTEGA KEULE AND LANDON/A CALOPHYLLA NEW SPECIES 
PLATE7 

[All figures X 1] 

Figures 1-8. Foliage of extant Laurales 

1. Trimenia weinmanniaefolia Seem. (Trimeniaceae), U.S.G.S. Ref. Coli. no. 2320. 

2. Ascarina philippensis C.B. Rob. (Chloranthaceae), U.S.G.S. Ref. Coil. no. 11211. 

3. Hedyosmum arborescens Sw. (Chloranthaceae), U.S.G.S. Ref. CoiL no. 2330. 

4. Austrobaileya scandens C.T. White (Austrobaileyaceae), USNM Cleared Leaf no. 6415. 

5. Gomortega keule (Mol.) Baill. (Gomortegaceae), U.S.G.S. Ref. Coli. no. 2462. 

6. Amborella trichopoda Baill. (Amborellaceae), USNM Cleared leaf no. 4455. 

7. Hedycarya denticulata (A. Gray) Perk. & Gilg. (Monimiaceae), U.S.G.S. Ref. Coil. no. 10592. 

8. Idiospennum australiense (Diels) S.T. Blake (Idiospermaceae), U.S.G.S. Ref. Coil. no. 9650b, 9650c. 
US. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 7 

FOILAGE OF EXTANT LAURALES 
PLATE 8 

[All figures X 1 except where indicated) 

Figures 1-7. Pabiania variloba new species (p. 21) 

1. 15713-3546A. Typical trilobed leaf with well-preserved petiole. 

2. 15713-3320. Unlobed leaf with pinnate venation. 

3. 15713-3317'. Holotype. 

4. 15713-3327. Small trilobed leaf. 

5. 15713-3318, X 2. Small unlobed leaf showing well-developed lateral primary veins. 

6. 15713-4847, x 2. Trilobed leaf showing numerous galls (dark circular areas). 

7. 15713-3316, x 2. Fragmentary specimen showing the decurrent base and basilaminar secondary veins 

(arrows). 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 8 

PABIANIA VARILOBA NEW SPECIES 
PLATE 9 

Figures 1-3. Pabiania variloba new species (p. 21) 

1, 3. 15713-7801'. 

1. General view of shoot with attached leaves, x 2. 

3. Closeup of figure 1 showing two successive nodes bearing opposite leaves. The leaves of each node 

are labeled in acropetal sequence, x 4. 

2. 15713-4845, x 5. Closeup of trilobed leaf preserving primary veins (1 °), sinus (S), sinus bracing vein (Sb ), 

and tertiary and higher order venation. 

4, 5. Higher order venation of select extant Laurales, x 4 

4. Siparuna decipiens (Tul). A.Dc. (Atherospermataceae), U.S.G.S. Ref. Coli. no. 9203. Note strong 

venational similarities to Pabiania. 

5. Sassafras albidum (Nutt.) Nees. (Lauraceae), U.S.G.S. Ref. Coli. no. 772. Note the uniform divergence 

angles for the quaternary and quintary venation and the regularity in areolar size and shape. This syndrome 

of features characterizes both Sassafras and Lindera. 
U S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 9 

PABIANIA VARILOBA NEW SPECIES AND SELECT EXTANT LAURALES 
PLATE 10 

[All figures x 1) 

Figures 1-7. Foliage of extant Laurales with similarities to Pabiania and Pandemophyllum 

1. Appolonias canariensis (Lauraceae), U.S.G.S. Ref. Coli. no. 9615b. Note the strong distinction between 

petiole and blade and the orthogonal reticulate higher order venation, in contrast to Pandemophyllum. 

2. Illigera vespertilla (Benth.) Baker f. (Hemandiaceae), U.S.G.S. Ref. Coli. no. 2828b. Note the welldeveloped lateral primacy veins and the irregular higher order venation. 

3. Sipanma decipiens (Tul) A.Dc. (Atherospermataceae), U.S.G.S. Ref. Coli. no. 9203. 

4. Sparattanthelium tupiniquinornm Mart. (Gyrocarpaceae), U.S.G.S. Ref. Coli. no. 9091. 

5. Hortonia angustifolia (Thw.) Trim. (Hortoniaceae), U.S.G.S. Ref. Coli. no. 4492. 

6. Eusideroxylon zwageri T. & B. (Lauraceae), U.S.G.S. Ref. Coli. no. 3266a, 3266b. Note general similarities 

in secondary and tertiary venation to Pandemophyllum. 

7. Sassafras albidum (Nutt.) Nees (Lauraceae), U.S.G.S. Ref. Coli. no. 771. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 10 

FOILAGE OF EXTANT LAURALES 
PLATE 11 

[All figures x 400 unless otheiWise indicated) 

Figures 1-7. Cuticle of Pabiania variloba new species (p. 21) 

1, 2. 15713-4875A. 

1. Upper cuticle showing two small trichome bases (arrows) and numerous laminar resin bodies, 

X 160. 

2. Closeup of trichome base in the upper right comer of figure 1, x 400. 

3. 15713-4847A. Closeup of well-preserved laminar secretory body, x 512. 

4-7. 15713-3314B. 

4. Three stomata showing paracytic (P) and laterocytic (L) subsidiary cell arrangement. 

5. Weakly cyclocytic stomatal complex (center). 

6. Region beneath primary vein, lower cuticle, showing numerous idioblasts (regions with thickened 

cuticle). 

7. Region beneath higher order vein, lower cuticle, with trichome base (TB) and idioblast (I). 

8. Lower cuticle of Sassafras albidum (Nutt.) Nees (Lauraceae), University of Florida Modem Leaf Ref. CoiL no. 19, 

photographed under phase-contrast light microscopy, x 640. Note the general similarities to Pabiania in the 

construction of the stomatal complex but the more uniform arrangement of subsidiary cells. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 11 

CUTICLES OF PABIANIA VARILOBA NEW SPECIES AND SASSAFRAS ALB/DUM 
PLATE 12 

[All figures x 1 unless otherwise indicated] 

Figures 1-8. Pandemophyllum kvacekii new species (p. 26) 

1. 5713-4800A. Specimen showing elliptic shape typical for species. 

2. 15713-4797. Apical half of leaf showing subrhombiodal shape. 

3. 15713-8300. Specimen showing somewhat ovate shape. 

4. 15713-3672. Specimen showing petiole. 

5. 15713-4716. Incomplete leaf showing transversely oriented tertiary venation. 

6. 15713-7851, x2. Small leaf showing gradation between petiole and blade. 

7. 15713-4799, x 2. Base of leaf showing cuneate shape and weak development of basilaminar secondary 

veins. Note leaf mines in the upper right-hand corner of photograph. 

8. 15713-7877. Holotype (leaf in center of photograph). 
US. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 12 

PANDEMOPHYLLUM KVACEKII NEW SPECIES 
PLATE 13 

Figures 1, 2. Pandemophyllum kvacekii new species, 15713-4797 (p. 26) 

1. Apical region of specimen in plate 12, figure 2, x 5. 

2. Enlargement of the upper left-hand region of figure 1, x 15. Note the secondary vein (2°), reticulate tertiary 

venation, and tendency for the quaternary veins to ramify. The quinternary veins show strong reticulate 

tendencies and enclose minute (0.1 mm diameter) areoles. 

3-5. Pandemophyllum attenuatum new species. (p. 29) 

3. 15713-7845, x 1. Holotype. 

4. 15713-4898a, 4898b, x 1. Both specimens show the extremely long attenuate apex characteristic of this 

species. 

5. 15713-8305, x 2. Fragment preserving apical region of leaf showing flattened brochidodromous arches. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 13 

5 

PANDEMOPHYLLUM KVACEKII AND PANDEMOPHYLLUM A TTENUA TUM NEW SPECIES 
PLATE 14 

Figures 1-4. Fossil leaves with similarities to Pandemophyllum, x 1 

1. "Inga" cretacea, USNM 2767 A. Dakota Formation, Kansas. 

2. "Salix" deleta, USNM 50038. Dakota Formation, Kansas. 

3. Myrtophyllum geinitzii, USNM 326818. Woodbine Formation, Texas. 

4. Proteoides daphnogenoides Heer, paratype, USNM 665. Note the absence of well-preserved venation above 

the first order. Dakota Group, northeastern Nebraska. 

5, 6. Pandemophyllum sp. 15713-4827 (p. 30) 

5. General shot of single preserved leaf, x 2. 

6. Closeup of figure 5 showing the flattened brochidodromous arches of the secondary veins and the thick, 

apically oriented tertiary veins, x 5. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 14 

6 

FOSSILS SIMILAR TO PANDEMOPHYLLUM, AND PANDEMOPHYLLUM SP. 
PLATE 15 

Figures 1-9. Cuticle of Pandemophyllum kvacekii new species (p. 26) 

1. 15713-3671C(1), x 400. General shot of upper cuticle showing well-developed trichome bases. 

2. 15713-3323B(2), x 160. Flake of wax. 

3. 15713-3671B(2), x 160. Laminar resin bodies. 

4. 15713-3667B(1), X 400. General view of lower cuticle showing numerous brachyparactytic stomatal 

complexes and a cluster of trichome bases (center of photograph). 

5. 15713-3671C(2), x 640. Amphibrachyparacytic stomatal complex and associated trichome bases. Note how 

the lamellar cuticular thickenings are located only on the tangential walls of the guard cells and the inner 

pair of subsidiary cells. 

6. 15713-3671B(1), x 512. Two stomatal complexes showing the weak development of lamellar thickenings 

over the inner pair of subsidiary cells .. 

7. 15713-3671B(1), x 512. Stomatal complex showing the development of one lamellar thickening only at the 

junction of the guard cell and inner subsidiary cell (arrow). Note large resin body in top right corner of 

photograph. 

8. 15713-3323B(1), x 400. Upper cuticle over midvein showing numerous trichome bases. 

9. 15713-3671B(1), x 160. Lower cuticle under midvein. Note large resin bodies in top half of photograph. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 15 

CUTICLE OF PANDEMOPHYLLUM KVACEKII NEW SPECIES 
PLATE 16 

Figures 1-6. Cuticle of Pandemophyllum attenuatum new species (p. 29) 

1-4, 6. 15713-4698A. 

1. Phase contrast, general view of upper cuticle, x 160. 

2. Phase contrast, area over a higher order vein, upper cuticle, showing undulatory pattern 

characteristic of this species, x 160. 

3. Phase contrast, lower cuticle showing brachyparacytic stomatal complex. NOTE: The cuticle of 

the subsidiary cells is not thinner than that of the unspecialized epidermal cells, x 400. 

4. Phase contrast, trichome base with angular pore (arrow), x 400. 

6. Lower cuticle beneath primary vein. Note the weakly developed undulations, in contrast to the 

regions beneath higher order veins, x 160. 

5. 15713-4898B. Phase contrast microscopy, lower cuticle, trichome base with circular pore, x 400. 

7-9. Cuticle of Pandemophyllum sp. (p. 30) 

7, 8. 15713-4827. 

7. Phase contrast microscopy, general view, upper cuticle, x 400. 

8. Phase contrast microscopy, stomatal complex on upper cuticle (arrow), x 400. 

9. 15713-4827' (counterpart). General view of lower cuticle showing numerous brachyparacytic 

stomatal complexes with thin cuticle on the outer pairs of subsidiary cells, x 160. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 16 

CUTICLES OF PANDEMOPHYLLUM A TTENUA TUM NEW SPECIES AND PANDEMOPHYLLUM sp. 
PLATE 17 

Figures 1-3. Cuticle of Pandemophyllum sp. 15713-4827' (p. 30) 

1. Stomatal complexes, x 512. 

2. Upper cuticle above midvein showing cells organized into weakly defined rows and scattered idioblasts 

(heavily cutinized cells), x 160. 

3. Lower cuticle beneath midvein with numerous idioblasts/trichome bases, x 400. 

4-7. Cuticles of extant Lauraceae 

4. Ocotea tristis, University of Florida Modern Leaf Ref. Coli. no. 182, upper cuticle showing trichome base 

of the Pandemophyllum type, x 512. 

5, 6. Ocotea bracteata, University of Florida Modern Leaf Ref. Coli. no. 221, x 640. 

5. Partially macerated stomatal complex (center) showing narrow pair of inner subsidiary cells (arrows). 

6. Fully macerated stomatal complexes. 

7. Nectandra tarascensis, University of Florida Modern Leaf Ref. Coli. no. 32, stomata showing welldeveloped lamellar cuticular thickenings on the guard cells, x 640. 

8, 9. Cuticle of Staudtia gabonensis (Myristicaceae), U.S. National Herbarium no. 1750180, x 640 

8. General view of stomata showing well-developed lamellar cuticular thickenings on the guard cells and 

brachyparacytic subsidiary cell arrangement. 

9. Trichome base typical ofMyristicaceae (center) showing a circular trichome abscission scar positioned over 

modified cells. 
U.S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 17 

CUTICLES OF PANDEMOPHYLLUM SP., EXTANT LAURACEAE, AND STAUDT/A GABONESIS 
PLATE 18 

[All figures X 1 unless otherwise indicated] 

Figures 1-7. Longstrethia varidentata new species (p. 31) 

1. 15713-4893A', specimen showing gradually narrowed base of leaf and indistinct petiolar region. 

2. 15713-4906a, 4906b. Note curvature in 4906a. 

3. 15713-4715, x 2. Note teeth along right-hand margin of leaf. 

4. 15713-4961a, 4961b, 4961c. Specimens showing coarsely dentate margins. 

5, 6. 15713-8301. 

5. General view of specimen showing intramarginal vein, x 2. 

6. Closeup of apical region of specimen showing round, non-glandular tooth (left margin) and 

irregularly reticulate higher order venation, x 10. 

7. 15713-7806, x 4. Specimen preserving tip of leaf and coarsely dentate margin. 
U S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 18 

LONGSTRETH/A VARIDENTATA NEW SPECIES 
PLATE 19 

Figures 1-9. Cuticle of Longstrethia varidentata new species (p. 31) 

1, 2, 5, 7-9. 15713-3693A. 

1. General view of upper cuticle, x 160. 

2. General view of lower cuticle, x 160. 

5. High-contrast photograph of stoma showing the curved lamellar cuticular thickenings on 

the guard cells, x 640. 

7. Epidermal secretory cell (arrow) surrounded by 5 radially oriented unspecialized cells, 

x400. 

8. Epidermal secretory cell with attached resin body (arrow), X 512. 

9. Laminar resin body, interpreted as mesophyll secretory cell, x 512. 

3. 15713-3668A, x 512. Stomatal complex with tendency towards cyclocytic arrangement of 

subsidiary cells. Here only the upright portion of the T -piece is well developed, and the lower 

T -piece flares towards the stomatal pole. · 

4. 15713-3691A, x 400. Laterocytic stomatal complex and associated idioblast (arrow). In this 

stoma, both the upright and the crossbar of the T -piece are present. 

6. 15713-3684B, x 640. High-contrast photograph of a stoma showing striations on the guard cells 

oriented concentric to the stomatal pore. 
U S. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 19 

CUTICLE OF LONGSTRETH/A VARIDENTA TA NEW SPECIES 
PLATE 20 

Figure 1. Lower cuticle of Longstrethia varidentata beneath midvein, 15713-3693A, x 160 (p. 31) 

2-5. Cuticles of extant Illiciales. 

2, 3. lllicium parviflorum Michx (Illiciaceae), MICH, L.R. Holdridge no. 2124. 

2. Lower cuticle, phase contrast, x 256. 

3. Stoma with T -pieces, x 400. 

4. Illicium floridanum Ellis (Illiciaceae ), MICH, A. Jewett no. 1046. Phase contrast, lower cuticle with 

secretory cell (lower left corner), x 400. 

5. Kadsura japonica Dun. (Schisandraceae), MICH, 0. Yongsok no. 8209. Stoma showing oval 

lamellar thickenings on outer walls of guard cells and striations concentric to the stomatal pore, 

x640. 

6-9. Foliar architecture of extant Illiciales 

6, 8. lllicium temstroemoides A.C. Smith (Illiciaceae), USNM Cleared Leaf no. 770. 

6. X 1. 

8. x3. 

7, 9. Schisandraceae 

7. Kadsura oblongifolia Merr., USNM Cleared Leaf no. 784, x 1. 

9. Kadsura phillipensis Merr., USNM Cleared Leaf no. 403, closeup of secondary and higher order 

venation, x 5. 
U S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 20 

8 

CUTICLES OF LONGSTRETH/A VARIDENTATA; CUTICLES AND VENATION OF EXTANT ILLICIALES 
PLATE 21 

[All figures x 1 unless othetwise indicated] 

Figures 1-5. Didromophyllum basingerii new species (p. 34) 

1. 15713-4699a, 4699b. Specimen presetving a pair of laminar units on a single bedding plane. 

2. 15713-7863. Nearly complete specimen showing characteristic asymmetry in the divergence of the two 

primary veins at the base of the lamina. 

3. 15713-4895. Holotype. 

4, 5. 15713-7865. 

4. General view of specimen showing the tip of a lateral lobe (top), x 2. 

5. Closeup of specimen showing reticulate tertiary and higher order venation, well-developed 

areolation, and the apparent absence of freely ending veinlets, x 5. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 21 

DIDROMOPHYLLUM BASINGERII NEW SPECIES 
PLATE 22 

Figures 1, 2. Didromophyllum basingerii new species (p. 34) 

1. 15713-8302. Specimen shows the decurrent origin of one of the two primary veins at the base of the lamina. 

2. 15713-4895, x 2. Specimen illustrated on plate 21, figure 3, showing the nearly symmetrical bifurcation of the 

vascular tissue in the petiol(ul)e to form the two primary veins. 

3. "Sterculia" snowii var. disjuncta Lesquereux, USNM 2745, x 1. Note the similarity in the general organization of 

each laminar unit to that found in Didromophyllum and the connection of the two laminar units at the base of the 

specimen. 
U.S GEOLOGICAL SURVEY BULLETIN 1915 PLATE 22 

DIDROMOPHYLLUM BASINGER// NEW SPECIES AND "STERCULIA" SNOWII var. DISJUNCTA 
PLATE 23 

Figures 1-3. Acritodromum ellipticum new species, 15713-4704 (p. 36) 

1. General view of specimen after excavating basal region, X 1. 

2. High-contrast photograph of specimen taken before excavating basal region showing details of secondary 

and tertiary venation, x 2. 

3. Enlargement of figure 2, showing the irregular, sinuous tertiary venation and faint quaternary veins oriented 

at nearly right angles to the tertiary veins, x 5. 

4-6. Reynoldsiophyllum masonii (Lesquereux) new combination (p. 37) 

4, 6. USNM 50077. 

4. General view of specimen, x 1. 

6. Closeup of tooth, x 10. 

5. USNM 2779, x 1. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 23 

ACRITODROMUM ELLIPTICUM NEW SPECIES AND REYNOLDSIOPHYLLUM MASONII NEW COMBINATION 
PLATE 24 

[All figures x unless othetwise indicated] 

Figures 1-5. Reynoldsiophyllum nebrascense new species (p. 39) 

1, 2, 4. Holotype (part and counterpart). 

1. 15713-7805'. 

2. 15713-7805. 

4. 15713-7805', x5. Enlargement showing transversely oriented tertiary veins and curved, 

reticulate quaternary veins. 

3, 5. 15713-4876. 

3. X 1. 

5. x 5. Note the uniform thickness of the structural reinforcement of the margin and the root 

penetrating the midvein of the leaf (arrows). 
US GEOLOG ICAL SURVEY BULLETIN 191 5 PLATE 24 

3 

4 5 

REYNOLDSIOPHYLLUM NEBRASCENSE NEW SPECIES 
PLATE 25 

Figure 1. "Elaeodendron" speciosum Lesquereux, UKSM DT-13, X 1 

2, 3. Dicotylophyllum angularis, 15713-4882A (p. 40) 

2. X 1. 

3. Closeup of basal part of leaf showing cuneate base and thin secondary veins (arrows), x 2. 

4-6. New genus B (p. 41) 

4, 6. 15713-4850. 

4. General shot, x 2. 

6. Closeup showing irregular secondary venation that forms loops near the margin and irregularly 

reticulate higher order venation, x 5. 

5. 15713-4831 ', X 2. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 25 

3 

"EIAEODENDRON" SPECIOSUM, DICOTYLOPHYLLUM ANGUIARIS, AND NEW GENUS B 
PLATE 26 

Figures 1-4. Anisodromum wolfei new genus and species (p. 42) 

1, 2. 15713-7803. 

1. General view of holotype showing three leaflets attached to the rachis, x 2. 

2. Closeup of attachment of leaflets to rachis, x 5. Note darkening along laminar margins, 

interpreted as the remains of structural reinforcement. 

3, 4. 15713-7802. 

3. General view of leaflet showing slight asymmetry to secondary venation, x 2. 

4. Closeup of middle portion of leaflet showing thin, sparsely branched, admedially oriented tertiary 

venation (poorly preserved), x 5. 
US GEOLOG ICAL SURVEY BULLETIN 1915 PLATE 26 

2 

ANISODROMUM WOLFE! NEW GENUS AND SPECIES 
PLATE 27 

Figures 1, 3, 4. Citrophyllum doylei new species, 15713-4894 (p. 43) 

1. General view of holotype, x 1. 

3. Closeup of base, showing alate petiole constricted at base of lamina, x 2 

4. Enlargement of upper left region of leaf showing curved eucamptodromous secondary veins and thin, 

sparsely branched, admedially oriented tertiary venation (poorly preserved), x 3. 

2. Citrophyllum aligerum (Lesquereux) Berry, USNM 50128, X 1. 
U.S. GEOLOGICAL SURVEY BULLETIN 1915 PLATE 27 

4 

CITROPHYLLUM DOYLE! NEW SPECIES AND CITROPHYLLUM ALIGERUM 
PLATE 28 

Figures 1-5. Dicotylophyllum myrtophylloides new species, 15713-8303 (p. 45) 

1. General view of specimen showing four leaves attached to axis, x 3. 

2. Enlargement of figure 1 showing attachment of basal leaf to axis, x 6. 

3. Enlargement of apical region showing attachment of terminal three leaves to axis, x 10. The linear 

markings are gouged areas in the matrix. 

4, 5. Enlargements of different leaves showing details of secondary venation and poorly preserved, irregularly 

reticulate tertiary venation, x 10. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 28 

DICOTYLOPHYLLUM MYRTOPHYLLOIDES NEW SPECIES 
PLATE 29 

Figures 1-5. Dicotylophyllum rosafluviatilis new species (p. 46) 

1, 2, 4, 5. 15713-4698. 

1. General view of holotype, x 1. 

2. Closeup of base showing petiole, basilaminar secondary veins, and recurved superadjacent 

pair of secondary veins, x 5. 

4. Closeup of highly branched secondary vein on right side of specimen showing exmedial 

branch of secondary vein (arrow), tertiary veins, and irregular quaternary venation (poorly 

preserved), x 10. 

5. Margin showing darkened region and teeth, x 10. 

3. 15713-4698' (counterpart). Apical region showing thin, admedially oriented tertiary venation, x 5. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 29 

5 

DICOTYLOPHYLLUM ROSAFLUVIA TILlS NEW SPECIES 
PLATE 30 

Figures 1-5. Dicotylophyllum aliquantulisetTatum new species (p. 47) 

1, 4. 15713-4877A, 4877B, holotype. 

1. Pair of laminae on bedding plane, x 1. 

4. Closeup left lamina showing crenate margin and thinning of secondary veins near margin, x 10. 

2. 15713-4707, x 2. Note tendency for each secondary vein to form its own series ofbrochidodromous loops. 

3, 5. 15713-7804. 

3. General view of specimen, x 2. 

5. Enlargement of apical region showing serrate margin and breaks in the lamina that may represent 

venation, x 10. 
US GEOLOGICAL SURVEY BULLETIN 1915 PLATE 30 

3 

4 5 

DICOTYLOPHYLLUM ALIQUANTULISERRA TUM NEW SPECIES 
PLATE 31 

Figures 1-4. Dicotylophyllum expansolobum new species (p. 48) 

1. 15713-8304', counterpart, x 1. 

2-4. 15713-8304. 

2. X 1. 

3. Enlargement of middle sinus showing shape and darkened region along margin, interpreted as 

structural reinforcement, x 5. 

4. Enlargement of two vertical lobes in figure 2 showing small teeth along margin (arrows), x 10. 
U.S GEOLOGICAL SURVEY 1 BULLETIN 1915 PLATE 31 

DICOTYLOPHYLLUM EXPANSOLOBUM NEW SPECIES 

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