SMITHSONIAN COKTRIBUTIOSS TO BOTANY NUMBER 59 

Classification of the Outlying 

Species of New World Panicum 

(Poaceae: Paniceae) 

Fernando 0. Zuloaga 

and Thomas R. Soderstrom 

SMITHSONIAN INSTITUTION PRESS 

City of Washington 

1985 
ABSTRACT 

Zuloaga, Fernando O., and Thomas R. Soderstrom. Classification of the 

Outlying Species of New World Panicum (Poaceae: Paniceae). Smithsonian 

Contributions to Botany, number 59, 63 pages, 25 figures, 2 tables, 1985.- 

In the present study a number of species originally assigned to Panicum but 

not fitting tvell ivithin its boundaries have been examined. Some of the 

characters that have been used in the past to distinguish genera in the tribe 

have been re-examined, including type of hilum, spikelet compression, relative length of the glumes, consistency of the upper anthecium and whether 

crested or not, and carriage of the spikelet relative to the axis. Further 

characters of taxonomic importance have been revealed by studies made lvith 

the scanning electron niicroscope (SEM) at higher magnifications than previously possible. The results of these studies indicate that several species 

should be removed from Panicum and transferred to other genera. Accordingly the following changes have been made: P. megastachyum Nees ex Trinius 

and P. albicomum Sr%.allen & Garcia Barriga have been transferred to Brachiaria, P. glutinosum Swartz and P. villaricense Mez to Homolepis, P. grandifolium Doell to Ichnanthus, P. killipii Hitchcock to Paspalurn, and P. macranthum Trinius to Streptostachjs. Panicum arnacites Trinius forms the basis of a 

net\ genus, Tatianjx. U'ith these changes in content the descriptions of 

Homolepis and Streptostachjs are emended, two new species-Brachiaria tatianae and Streptostachjs ramosa-are described, and the unusual species P. 

aristellum Doell is characterized and a possible relationship discussed. A chart 

is presented that conipares the characters of the genera covered in the 

present investigation, P. aristellum and the ttvo new species are illustrated, 

and SEX1 photomicrographs of all taxa are included. 

OFFICIAL PUBLICATION DATE is handstamped in a limited number of initial copies and is 

recorded in the Institution's annual report, Smithsonian Year. SERIES COVER DESIGN: Leaf 

clearing from the katsurd tree Cerczdzphyllum japonicum Siebold & Zuccarini. 

Library of Congress Cataloging in Publication Data 

Zuloaga, Fernando. 

Classification of the outlying species of New W'orld Panicum (Poaceae: Paniceae). 

(Smithsonian contributions to botany ; no. 59) 

Bibliography: p. 

Sum. of Docs. no.: SI 1.29:59 

1. Panicurn-Classification. 2. Grasses-America-Classification. 3. Grasses-Classification. 4. Botany-America-Classification. I. Soderstrom, Thomas R. 11. Title. 111. 

Series 

QKl.S2747 no. 59 [QK49.5.G54] 581s [584'.92] 84-600221 
Contents 

Page 

Introduction ............................................ 1 

Methods and Materials ................................. 3 

Key to the Genera of Paniceae .............................. 3 

Brachiaria .............................................. 4 

Brachiaria megastachya. new combination ..................... 5 

Brachiaria tatianae. new species ............................ 7 

Brachiaria albicoma. new combination ....................... 11 

(Comparison of Hornolepis and Panicum) ...................... 11 

Key to the Species of Homolepis ............................ 

Hornolepis aturensis ...................................... 15 

Acknowledgments .................................... 3 

Hornolepis. emended ...................................... 14 

14 

Hornolepis glutinosa. new combination ....................... 19 

Hornolepis isocalycia ...................................... 24 

Hornolepis longispicula ................................... 27 

Homolepis villaricensis. new combination ..................... 29 

Ichnanthus .............................................. 31 

Ichnanthus grandifolius. new combination .................... 31 

(Taxonomic Position of Panicum aristellum) .................... 33 

Panicurn ................................................ 36 

Panicum aristellum ...................................... 36 

(Taxonomic Position of Panicum killipii) ...................... 40 

Paspalurn ............................................... 40 

Paspalum killipii. new combination ......................... 40 

(Taxonomic Position of Streptostachys) ........................ 42 

Streptostachys Desvaux. emended ............................. 46 

Key to the Species of Streptostachys ......................... 46 

Streptostachys asperifolia .................................. 47 

Streptostachys macrantha. new combination .................... 50 

Streptostachys ramosa. new species ........................... 52 

(Taxonomic Position of Tatianyx) ........................... 53 

Tatianyx Zuloaga & Soderstrom. new genus .................... 56 

Tatianyx arnacites. new Combination ........................ 56 

Literature Cited ......................................... 61 

... 

111 

Classification of the Outlying 

Species of New World Panicum 

(Poaceae: Paniceae) 

Fernando 0. Zuloaga 

and Thomas R. Soderstrom 

Introduction 

The genus Panicum, described by Linnaeus in 

1753, is one of the largest genera of grasses, with 

approximately 600 species of worldwide distribution; the majority of these are tropical or subtropical. Because of its size and widespread occurrence the genus has been subjected to the 

scrutiny of many investigators but none has studied it in its entirety. The African members received a rather thorough review in the early part 

of this century by Otto Stapf of Kew, who allocated them to a number of sections. On this side 

of the Atlantic the American agrostologists 

Alfred S. Hitchcock and Agnes Chase made detailed studies of the North American species and 

grouped most of them according to natural affinity. Their chief studies were published in “The 

North American species of Panicum” in 19 10 and 

“‘Tropical North American species of Panicum” 

in 1915. Chase also wrote a series of papers 

(1906, 1908, 191 1) giving decailed analyses of 

New World genera in the tribe Paniceae. Among 

the most recent works on Panicum and allied 

genera is that of Pilger (1 93 l), who divided the 

genus into eight subgenera and 11 sections, and 

of Hsu (1965), who made a complete analysis of 

the tribe-Panicum in particular-reorganizing 

it into five subgenera and 25 sections. Hsu utilized newly recognized characters pertaining to 

such structures as the ligule, midnerve of the 

blade, lodicules, and epidermis of the leaf and 

upper lemma. 

Since the time of Chase, especially during the 

past decade, herbarium holdings of tropical 

American Panicum have expanded dramatically 

due to an increase in collecting activity. As new 

species have been described and known ones 

restudied, the most interesting problems have 

continued to be the delimitation of the genus 

itself and its position within the tribe. 

In the present study we have examined a number of species that were originally described in 

Panicum but did not seem to be well accommodated in it. This review has prompted us to reexamine some of the characters that have been 

used in the past to distinguish genera in the tribe, 

such as type of hilum, spikelet compression, relative length Of the glumesj consistency Of the 

upper anthecium and whether crested or not, 

and carriage Of the ’pikelet relative to the axis. 

Some of the most important characters that we 

Fernando 0. Zuloaga, Instituto de Botanica Danuinion, Casilla 

de Correo 22, Sun Isidro, Argentina. Becario del Consejo Nacional de Investigaciones Cientijicas y Tecnicas (CONKET) de 

la Republica Argentina. Thomas R. Soderstrom, Department of 

Botany, A’ational Museum of Natural History, Smithsonian Institution, Washington, D. C. 20560. 

1 
2 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

\ IL 

I I I I 

I I I I 

1 I I 

(d 

n 

33 
NUMBER 59 3 

have found to be of generic value are illustrated 

in Figure 1. 

Information derived from studies made with 

the scanning electron microscope (SEM) on the 

surface of the lemmas and paleas of the upper 

floret has been especially useful in the present 

study. Characters revealed at the higher magnifications often corroborate decisions based on 

gross morphology. 

We have concluded that several species described in Panirum should be transferred to other 

genera, such as Brachiaria, Ichnanthus, and Paspalum. One of the species does not fit within the 

boundaries of any described genus and we are 

thus elevating it to that rank with the name of 

Ta tia njx . 

A study of gross morphological characters as 

well as those revealed by the SEM should be 

extended to all species of Panicurn. When these 

data are collected for the entire genus we will be 

able to compare them more meaningfully and 

arrive at a fuller understanding of the genus and 

relationships of allied taxa. 

Rather than refer to the two florets (anthecia) 

of the typical panicoid spikelet as fertile and 

sterile, we designate them by their position in the 

spikelet. The fertile antheciuni is thus the “upper 

anthecium” and rvhat is usually called the sterile 

floret is referred to as the “lower anthecium.” 

This avoids the biased use of the word sterile, 

which is really incorrect, because this floret or 

anthecium usually contains stamens. Our use of 

the term anthecium is for the unit that includes 

the lemma and palea and when we refer to these 

structures we again use their position: upper 

lemma, upper palea, lower lemma, lower palea. 

As the earlier spelling of “oecology” has given 

way to “ecology” and ”gynoecium” to “gynecium” 

in modern American usage, we have adopted 

these more evolved forms. Following the same 

rules we are also using “anthecium” and “andrecium” instead of “anthoecium” and “androeci u m . ” 

Data in “Additional Specimens Seen” and “Paratypes” sections have been quoted from specimen 

labels without editing, except for abbreviations 

of distance and direction. 

A synopsis of New World Paniceae is reflected 

in the Contents, with background notes and comparisons set off with angle brackets. 

nomic methods have been used in the present 

study, utilizing a Wild M5 dissecting microscope 

and Leitz Ortholux compound microscope. Observations at higher magnification were made 

using the scanning electron microscope. For 

these studies, anthecia were removed from dried 

herbarium specimens, secured on stubs, carbon 

coated in a vacuum evaporator, and then coated 

with a gold-palladium alloy. The specimens so 

treated were then viewed in a Cambridge S4- 10 

or Cambridge Stereoscan 2.50 Mk 2 scanning 

electron microscope operating at 1 0-20 kV. 

In addition to the extensive herbarium collections available at US, we relied on specimens lent 

by the following herbaria: B, BAA, BAF, CTES, 

F, GH, LIL, LP, M, MO, NY, S, and SI. 

grateful to the Consejo Nacional de Investigaciones Cientificas y Tecnicas de la Replublica 

Argentina (CONICET) for a grant that allowed 

him to spend two years (1 982-1 983) at the 

Smithsonian Institution as a post-doctoral fellow. 

The junior author appreciates the opportunity 

afforded him by the New York Botanical Garden 

to participate in an expedition to the Brazilian 

cerrados in 1964, at which time he collected 

material of the new genus Tatianyx. To Ms. Alice 

Ruth Tangerini we are both indebted for her 

skillful rendering of the illustrations of panicoid 

grasses in this paper and the chart of genera and 

characters depicted in Figure 1. 

METHODS AND MATERIALS.-ClaSSiCal tax@ 

ACKNOWLEDGMENTS.-The senior author is 

Key to the Genera of Paniceae 

(Acroceras and Hymenachne are not treated in this paper) 

1. Hiluni of caryopsis linear . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 

2. Spikelets densely villous and positioned obliquely on the falcate pedicel, with a callus on the 
4 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

dorsal face ............................................. .Tatianyx, new genus 

2. Spikelets glabrous and positioned evenly on the truncate pedicel, without a callus ..... .3 

3. Lower and upper glumes equal in length, shape, and nervation; upper anthecium 

chartaceous with the margins of the lemma flat, the lemma not crested at the apex and 

rachilla not thickened between the lower glume and upper anthecium ............. 

Lower glunie shorter than the upper, differing in shape and nervation; upper anthecium 

indurate with the margins of the lemma inrolled, the lemma crested at the apex or with 

the rachilla thickened between the lower glume and the upper anthecium ........ ,4 

4. Upper anthecium crested at the apex; rachilla not thickened between the lower 

4. Upper anthecium not crested at the apex; rachilla thickened between the lower 

.................................................. Homolepis, emended 

3. 

glume and upper anthecium .................................. Acroceras 

glume and upper anthecium ...................... Streptostachys, emended 

1. Hilum of caryopsis punctiform, rarely oblong. .................................... .5 

5. 

5. 

Upper anthecium membranous, hyaline, with the palea free at the apex, not covered by the 

lemma; lower palea absent; panicles spiciform to contracted, dense ......... Hymenachne 

Upper anthecium indurate, when membranous the palea completely covered by the lemma 

at its apex; lower palea sometimes present; panicles lax to contracted, rarely spiciform . , .6 

6. Spikelets with the back of the upper lemma turned away from the rachis, the lower 

glume facing it .............................................. Brachiaria 

6. Spikelets with the back of the upper lemma facing the rachis, the lower glume turned 

awayfromit ........................................................ 7 

7. Upper anthecium with appendages or “excavations” at the base; spikelets keeled 

and somewhat compressed laterally ........................... Zchnanthus 

7. Upper anthecium without appendages or “excavations” at the base; spikelets not 

keeled nor compressed laterally ..................................... .8 

8. Spikelets plano-convex, shortly pedicellate on unilateral racemes; lower glume 

cotnmonly absent, small when present ...................... Paspalum 

8. Spikelets biconvex, commonly arranged in panicles, less frequently in unilateral 

racemes, variously pedicellate; lower glume always present, variable in size . . 

..................................................... Panicum 

Brachiaria 

In 1853 Grisebach elevated to the level of 

genus the section Brachiaria of Panicum, which 

Trinius had established in 1826. As the typespecies of his new genus, Grisebach cited B. erucijormis (Panicum erucqorme Smith). Chase (1 9 1 1) 

accepted the genus and underscored its distinctive type of panicle and spikelets, the former 

consisting of spike-like racemes and the latter 

inverted in position, with the lower glume adjacent to the rachis. She also pointed out that the 

upper anthecium is frequently papillose-rugose, 

a character that Stapf (1 9 19) also used to delimit 

the genus. 

Hitchcock (1935, 1951), Gardner and Hubbard (1938), Pilger (1940, 1954), and JacquesF6lix (1 962), among others, considered spikelet 

position as an important character to differentiate the genus. Ascertaining the position of the 

lower glume in species with long pedicels, however, is difficult, but Gardner and Hubbard 

pointed out a way to overcome this. They suggested that the spikelet just below the terminal 
NUMBER 59 5 

one on the axis or on a branch of the panicle be 

examined to determine the position of the lower 

glume, because the spikelet is generally shortpedicellate and appressed to the rachis. They 

commented that the orientation is still occasionally unclear due to suppression or rudimentary 

development of the lower spikelet of the pair, in 

which case the terminal spikelet appears to be 

solitary and in an abaxial position. 

In 1969 Parodi, detailing and confirming the 

findings of Gardner and Hubbard, utilized the 

character of spikelet position in transferring to 

Brachiaria five species that had previously been 

included in the Fasciculata group of Panicum. In 

some of these-B. echinulata, B. lorentziana, and 

B. mollis-the spikelets are borne on rather long 

pedicels and their position is difficult to ascertain, 

a situation reminiscent of some African species 

such as Brachiaria ramosa (L.) Stapf and B. deflexa 

(Schumacher) Hubbard. Although she noted difficulty in differentiating the Brazilian species of 

Brachiaria on the basis of spikelet position, Sendulsky (1 978) accepted the character as valid and 

did not provide further ones. 

Unlike previous authors, Blake (1 958) did not 

consider spikelet position a definitive enough 

character to separate Brachiaria from Panicum, 

offering other characters instead: the texture of 

the upper anthecium, presence or absence of a 

rupture line, and type of areole on the dorsal 

face of the upper lemma toward its base. According to him, 

In one, characteristic of Panicum subgen. Panicum (the 

Panicum type), the fertile floret is more or less biconvex 

and muticous with the lemma smooth over the whole of 

the back and the rupture line and areole resemble the 

rest of the back in surface in curvature. In the trend 

represented by Urochloa (Urochloa-type), the fertile floret 

is plano-convex or nearly so, sometimes apiculate or 

aristulate, with the lemma more or less strongly transversely rugose, the rupture line is prominent and the 

areole more or less flattened or depressed, less rugulose 

than elsewhere. 

Unfortunately, these characters are not invariable. Pohl (1 980) discounted the presence or absence of a rupture line as a generic character in 

the Paniceae; and while the texture of the upper 

anthecium may be rugose or papillose in most 

Brachiarias, it is smooth in the type species! Panicum maximum, P. millegrana, P. sellowii, and P. 

trichoides are examples of species in which the 

upper anthecium is rugose. 

In the present study spikelet position is considered to be of generic value, in concordance with 

most agrostologists, and is the basis on which we 

are transferring the following species of Panicum 

to Brachiaria: P. megastachyum Nees ex Trinius, 

1826; P. megastachyum Nees, 1829, not Nees ex 

Trinius, 1826; and P. albicomum Swallen 8c Garcia-Barriga. 

Brachiaria megastachya (Nees ex Trinius)

Zuloaga 8c Soderstrom, new combination 

FIGURE 2 

Panicum megastachyum Nees ex Trinius, 1826:205. [Type: 

“V. spp. Brasil. Langsdorff.” Holotype, LE, not seen; 

fragment of the type, US sheet no. 974713. “In saxosis 

umbrosis Serra da Lapa,” cited under Panicum megastachyum Nees, 1829: 155, refers to this specimen.] 

Plants perennial (?), the base not seen. Culms 

cylindrical, hollow, glabrous. Nodes obscure, glabrous. Sheaths pale, glabrous. Ligule -1.5 mm 

long, membranous, long-ciliate above; collar glabrous, inconspicuous. Blades lanceolate, acuminate, flat, approximately 12 cm long, 0.8-1 cm 

wide, subcordate with the adaxial surface pubescent, the abaxial glabrous and margins scabrous. 

Panicles lax, diffuse, many-flowered, -25 cm 

long, 10 cm wide, the branches alternate to 

subopposite and diverging from the rachis, the 

spikelets diffused; axis angular, scabrous, with 

thick evenly distributed papillose-pilose hairs; 

branches hirsute with hairs similar to those present on the axis, the axils densely pubescent, the 

spikelets 2 or 3 on each branch, one subsessile, 

the other long-pedicellate, the pedicels 1-1 2 mm 

long, triquetrous, hirsute. Spikelets long-ellipsoid, 

3.8-3.9 mm long, 1.4-1.5 mm wide, stramineous 

to brown, with the lower glume adjacent to the 

rachis. Lower glume ovate, acute, 1.8-2.2 mm 
6 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 2.-L?rachiaria megastachya, new combination: a, upper anthecium, palea side (X 100); 

b, apex of lemma, detail of a showing flat macrohairs (X 400); c, upper anthecium, lemma side 

(X 100); d, detail of c showing simple papillae evenly distributed over the surface, making it 

rugose (X 500). All photomicrographs based on Riedel96 (US). 
NULIRER 59 7 

long, glabi.ous, 3-.?I-nerved, the nerves anastoinosed to\vard the glabrous to pubescent summit. 

1,Pper glume obtuse to subacute, 3.3-3.3 mm 

long, usually not covering the upper anthecium, 

5-7-nerved, the nerves anastomosed to\vard the 

sl1oi.t -lariat e sii iii 111 it . Louler lemma subacute, 

glume-like, lanate on the margins, 3.6-3.7 iiim 

long, .i-nei-ved, the nerves anastomosed. Lower 

pa lea iiai.imi.\.Iv el liptic, conspicuous, 3.2-3.4 nim 

long. 1 - 1.2 ii1111 it.ide, menibratious, glabrous 

mcept foi- flat Iiairs to\t.ard the apex; niale flower 

piwent jvitli 2 lodicules and 3 anthers, 2.2 mni 

long. [$per antherium nai-roivlv ellipsoid, acute, 

3.2-3.4 111111 long, 1.1-1.3 inn1 it.ide, plano-con- 

\.ex, st i.;im ineoiis to broiln, glabrous, covered 

\\.it11 evenl\. distributed simple or compound papillae, the apes of the upper lenlnia \%.it11 iiiimeroils hooks. (,'arjopsis not seen. 

~!I)DI-IION.AL SPECIMENS SEEN.-BRAZIL. M'ithout localit\-, Kieclel 96 (US), 1143 (SY). 

I)ISCL&N.-III 1829 Trinius added the folloiviiig d;ita iii his description of the species (as 

tl~anslated): 

(;ulins 1 .X-2.4 111 tall, cylindrical, glabrous, branching, 

shortly geniculate. Sheaths glabrous. Blades linear-lanceolate, flat. Panicle rniich-branched, with the branches 

spreading from the rachis, more than 30 cm long. 

IHis illusti.atioii depicts a much-branched panicle 

tvith spikelets occurring mostly in pairs on the 

i';iceiiies, one s~i bsessile and the other long-pedi- 

(el la t e. 

On a sheet ivith a fragment of the type speciiiieii ;it US, Cliase made the following annotat ion: 

Culms 4-6 ft., blades 1 ft. or more, Ih inch wide, glabrous, sheath wholly glabrous or silky on the collar, 

panicle about 1 ft., erect, contracted, rachis 8c branches 

mid pedicels pilose, spikelets about 4 mm, fruit slightly 

roughened, not shiny. Type of Nees ex Trin. 1826, not 

Nees ipse. 

Even tlioiigli the terminal spikelet in this species is boi-ne 011 a long pedicel, the inherent 

position of the spikelet is obvious in a subsessile 

meiiiber, ivhich al\vays occurs kvitti the lower 

glume adjacent to the rachis. 

Brachiaria tatianae Zuloaga & Soderstrom, 

new species 

FIGURES ?I, 4 

TYPE SPECIMEN.-BR~Z%I L, )TINAS (;ERAIS: 

" Habit ;at i 11 ii I ;i rg i n i b 11 s s y 1 va r ii I 11 D i s t r i c t 11 s Adamantum ad Tejuco etc. provinciae 5linaruni generaliiim." (Holotype, M; fi-agment of the Iiolotype, CS sheet no. 9747.52.) Basis of Panicum 

megastachyum Nees, 1829: 134, not Nees ex Ti+ 

iiiais, 1826. The specimeii rvxs collected bv Xlartius. 

Culmi erecti, simplices. Ligula membranaceociliata. Laminae lanceolatae, subcordatae. Paniculae lame, diffusae, pyramidales, 30-35 cm longae, 15-30 crn latae, raceinis spiciformibus spiculas binatas ferentibus. Spiculae ellipsoidae, 6- 

6.8 mm longae. Gluma inferna ovata longitudine 

lh spiculae aequans, 3-7-nervata. Gluma supera 

obtusa, 9-nervata. Lemma infernum 5-7-nervat ii 111 . Pa lea i 11 feima lo ti gi-el 1 i psoi dea , floi-em misculum gereiis. ;Znthoeciuni supei-iim longi-ellipso i de u ii i , g 1 ab 1. ti i I 1 , on I ii i ii o co ii fe rt i iii e t aeq 11 ;a 1 - 

iter papillosum; rhactiilla super- ;arithoecium siipei.um ex t ell sa. 

Perennial (?). the base not seen. (;ulms erect, 

c\,lindrical, sparsely pubescent near the nodes to 

glabrous, niany-noded, simple. ,Yodes brown, pubescent. Sheaths longer. than the internodes, 

-1 3-1.5 ciii long, pubescent, especially toiLxrd 

the upper part, pale. Ligule menibraiious, ciliate, 

- 1.5 iiini long; collar villous. Blades lanceolate, 

acuminate, flat or ivith involute niargins, -23 ciii 

long, 1 ciii ivide, rigid, subcordate at the base, 

pubescent 011 both surfaces, especially toward the 

base, the mai.gins smooth. Panicles lax, diffuse, 

pyi-amidal, many-floivered, 30-3.5 ciii long, 1 .?I30 ciii \tide, spikelets in pairs on spike-like racemes, one subsessile, the other short-pedicellate; 

axis angled, hispid, the branches alternate or 

subopposite, the lokver verticillate, diverging 

from the axis, naked at the base, hispid above, 

flexuous; pedicels 0.8-4 iiiiii long, shorter than 

the spikelets, triquetrous, \\'it11 long thick hairs 
FIGURE J.--Brachiaria tatianae, new species: a, habit of culm (X 1); b, panicle (X 1); c, spikelet, 

upper glume side (X 12); d, spikelet, lower glume side (X 12); e, upper anthecium, palea side 

(X 12);J; upper anthecium, palea side showing prolongation of rachilla (X 12); g, lower glume 

(X 12); h, upper glume (x 12); i, lower lemma (X 12); j, lower palea (X 12); k, spikelet, lateral 

view (X 12); I, branch of panicle (X 9); m, developed lemma of third anthecium (X 12); n, upper 

palea with gynecium and lodicules (X 12); 0, upper palea with stamens and lodicules (X 12). All 

draivings based 011 the holotype (M). 
NUMBER 59 9 

FIGURE 4.--Brachzaria tatzanae, new species: a, upper anthecium, palea side, showing compound 

papillae (X 1000); b, upper anthecium, palea side, showing apiculate summit of lemma and flat 

macrohairs (X 100); c, upper anthecium, palea side at base showing prolongation of rachilla (X 

50); d, detail of summit of lemma as shown in b (X 1000). All photomicrographs based on the 

I1olot)pe (M). 
10 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

toivard the apex and base. Spikelets ellipsoid, 6- 

6.8 iiiiii long, 2.2-2.4 niiii \t.ide, lanate on the 

apex of the gliinies and loiver lemnia, otherwise 

glabrous, tlie gl tiiiies and loi\.er lemma ivith 

pi-oiiiinent iien'es, the upper glunie, loiver 

lemma, and upper antliecium subequal. Lower 

glume o\'ate i\.itli ;I rounded to acute apex, 4-4.3 

nil11 long, half ;IS long ;is the spikelet or a little 

longer, 5-7-iierved, the nerves aiiastoiiiosed toi\.ai.d the apex, tlie summit and upper margins 

short-lanate. l'pper glume obtuse, j.3-6.3 iiim 

long. 9-nerved, Ianate, not covering the apex of 

the tipper antlieciuni. Lozler lemma glunie-like, 

aciite, 5.5-6.3 iiiiii long, .i-7-nerved, the nerves 

aiiastoniosed. Lorcer palea long-elliptical, 4.9-5.9 

miii long, 1.6-2.1 iiim [vide, membranous, shortpilose or glabi.oiis in the middle part and on the 

riiargins: niale flol\.er present ivith 2 lodicules 

and 3 ;intliei-s. Lpper anthecium long-ellipsoid, 

4.7-.5.9 iiiiii long, 1.6-2.1 iiiiii \vide, brown, 

densel!. papillose throughout, the papillae simple 

or coiiipouiid, tlie niargins of the lerii~iia covering the plea, [vitli iiuiiiei-ous hooks on the apex 

of the leriinia and flattened hairs on its upper 

iiiargins; i-acliilla pi~olonged into a short acute 

iiiiicro above the upper antliecium, conspicuous 

in txi-).ing degrees 011 different spikelets; lodiciiles 2, truncate; anthers 3, violet. Caryopsis not 

PARATYPE.-BRA%IL. "Panicum megastachyum. FI. Bras. \,arpeduizculis basi et apice barbatis, 

seen. 

Sellou~ 1276" (fragments, BAA, US sheet no. 

DrscvssrON.-In his De Graminibus Paniceis of 

1826, Trinius described niany species recognized 

bv C.G. Nees voii Esenbeck, indicating after each 

iiaiiie: "S. ah Es! iii Slai-t. FI. Bras. ined." Three 

years later Nees in his .Igrostologia Brasiliensis 

published these taxi ;is nelv, presumably unaivare 

that they had already appeared in print. In most 

of tlie species described-/'. chloroticum, P. elephantipes, P. decipiens, P. milioides, P. cyanescens, 

and P. ligulare, for example-the descriptions of 

both aiit1ioi.s refer to the same species and usually 

cite the saiiie type specimen. Hoivever, in at least 

tivo ciises the tvpe indicated bv both authors is 

different. One of these, P. campestre Sees ex 

Trinius. 1826, is a valid species of the Rudgeana 

gi-oup and distinct froni P. campestre Nees, 1829, 

ivhich is ;I valid species of the section Panicum. 

Henrard described the latter as new in 1940, 

giving it the 1i;iiiie of Panicum peladoense. 

The otlier case in \t.hich tivo species have masqueraded under the saiiie name is Panicum megastachpm. The trvo are characterized in Table 

1. 

Nees in fact referred to both specimens in his 

original desci-iption, the one a collection of Afartiiis and the other of Langsdorff. Hoivever, the 

description of Nees agrees closely ivith the Marti 11s specimen but not lvith that of Langsdorff. 

Ti-inius cited onlv the Langsdorff gathering. 

9 7 4 7 .i 2). 

TABLE 1 .-Comparison of P. megastachyum Nees ex Trinius and P. megastachyum Nees. 

P. megastachjum Nees ex Trinius, 1826 P. megastachyum Nees, 1829 

spikelets 3.8.-3.9 mtn long 

spikelets long-pedicellate 

rachilta not prolonged beyond the upper ant heci uni 

axis and branches hirsute with thick papillose-pilose hairs; pedicels hirsute with thin, 

evenly distributed hairs 

lower glume 3-5-nerved 

upper glume 5-7-nerved 

spikelets 6-6.8 mm long 

spikelets short-pedicellate 

rachilla prolonged as a conspicuous mucro 

beyond the upper anthecium 

axis and branches hispid with papillose-pilose 

hairs only at the base: pedicels papillozepilose at the apex and base 

lower glume 5-7-nerved 

upper glurne 9-nerved 
NUMBER 59 11 

Iloell (in llartius, 1877) reiterated what Nees 

had i.\.i-itten but noted that spikelet size and pubescence of the pedicels differed in the two specimens. Steudel (1 83.5) had also observed the difference in pedicel pubescence. 

Brachiaria albicoma (Swallen & Garcia 

Barriga) Zuloaga & Soderstrom, 

new combination 

FIGURE 5 

Panicum albicomum Swallen k Garcia Barriga, 1943:303, fig. 

c. [Type: (hlombia: "Dept. del Cauca. El Ramal to Rio 

Sucio, r\'est of Popayan, Cauca valley, Pennell 3 Killip 

8129." Holotype, US; isotypes, GH, NY.] 

Annuals 1.6-2 in tall. Culms cylindrical, erect, 

geniculate ;it the base, simple or branched, holIon., hispid. Sodes short- to long-pubescent r\.ith 

u.Iiitish hairs. Sheaths usually longer than the 

intei-nodes, 12- 19 cni long, densely to sparsely 

hispid, short-ciliate on the n~argins. Ligule membranous, ciliate, 1 - 1 .6 iiini long: collar lanate. 

H 1 a d es 1 i I i ea r- 1 an ce ol a t e , ac u ni i n a te , 1 8 - 2 4 c m 

long, 1.4- 1.8 cni \vide, flat, subcordate, densely 

Iiispid, especially toivard the base on the adaxial 

surfiice, tlie niai-gins scabrous lvith short, appressed hairs, tlie niidnerve prominent. Panicles 

oblong, lax, 22-30 cni long, 8-14 cni rvide, the 

bra n c h es xce n d i n g , t ti e s pi k el e t s short - pedi ce 1 - 

late in pairs or in threes, \$.ith the lower glume 

densely hirsute to villous, lvith long lvhitish hairs 

up to .5 nini long, thick toward the apex and Mith 

shorter hairs intermixed: the branches alternate, 

\\.idelv sp;iced and bearing spikelets to the base. 

Spikelets long-ellipsoid, 4.5-5.1 mm long, 1.6- 

I .8 nini \vide, glabrous, pale to dark purple, the 

glumes and lo\~.er lenirna Lvith thin nerves. Lower 

glume o\.ate, acute to obtuse, 1.9-2.5 nini long, 

;I third to tialf as long as the spikelet, 3-nerved, 

the apex scabrous. ["pper glume acute, 7-nerved, 

the nerves anastotnosed ton-ard the scabrous 

apex. Lower lemma glume-like, 7-nerved, the 

nerves anastoniosed toward the scabrous apex. 

L,ouler palea lanceolate, 3.7-3.8 nini long, 1.3 

f ,icing : the axis: branches and pedicels angular, 

mm \\ide, hyaline, glabrous; male floiver present, 

rvith 3 stamelis. Upper anthecium ovoid, 3.3-3.7 

nini long, 1.6-1.8 inin rvide, glabrous, stramineous to brorvn, transversely rugose, \\.ith round 

papillae distributed evenly; lemma apiculate, 5- 

nerved Ivith a scabrous apex: lodicules 2, truncate, plicate, enclosing the basal margins of the 

palea: Lvith 3 stamens. Caryopsis not seen. 

So far knoivn only from the Department of 

Cauca, Colombia, at elevations of 1600 to 1900 

ADDITIONAL SPECIMENS SEEN.--COLOILIBIA. 11Tithout state and locality, 'Llutis 5522 (US). 

CAUCA: El Tanibo, Garcia krriga 4426 (US): 

Chisquia, Finca Los Derrumbos, Asplund 10778 

(US). 

DIscussIoN.-This species is apparently most 

closely related to Brachiaria mollis (Srvartz) Parodi, lvhich differs in its smaller spikelets, 3.5-4 

nini long, and \\.idel- pubescent glunies. 

111. 

Comparison of Homolepis and Panicum 

Homolepis \\.as established in 19 1 1 by Agnes 

Chase, rvho based the genus on Panicum aturense 

H.B.K., deriving its name from the Greek homo 

(similar) plus lepis (scale), in reference to the 

subequal glumes. In addition to the type species, 

H. aturensis (H.B.K.) Chase, trvo further species 

were included: H. isocalyia (Meyer) Chase and 

H. longispicula (Doell) Chase, both transferred 

from Panicum, 

Diagnostic characters given by Chase Lvere the 

subequal glunies that are 7-9-nerved and enclose 

both anthecia; enclosure of the upper antheciuni 

by the leninia of the lotvei. aiitheciun~, Mhich is 

subequal to the glunies: and presence of a palea 

in the loiver antheciuni. Furtherinore, the upper 

antheciuni is not indurate but rather delicate and 

fragile and the margins of its leinnia are flat 

rather than inrolled, enclosing most of the palea. 

Several vegetative characters were also given for 

the genus: plants perennial, stoloniferous or 

creeping, decumbent and rooting on the loiver 

nodes. These latter characters, houever, do not 

apply to plants of H. longispicula, u,hich are ces- 
12 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE .i.-Brachiaria albicoma, new combination: a, upper antheciuni, lemma side, showing 

apiculate summit of lemma (X 1000); b, detail of lemma surface, shoiving rugose surface and 

simple papillae (X 200): c, upper antheciuni, lemma side at base, showing rupture line (X 70); 

d, upper anthecium, palea side, shoiving bicellular microhairs and prickle hairs (X 200). All 

photomicrographs based on Garcia Barrzga 4426 (US). 
NUMBER 59 13 

pitose, erect, and iii vegetative and habitat char- 

;icters totally distinct from the remainder of the 

species. Its spikelets, nevertheless, are those of 

Hornolepis. 

Regional floras \vith references to Hornolepsis 

include Hitchcock (1 9 13, 1922, 1927, 1930a,b), 

S~vallen (1 943, 19.55), Amshoff and Henrard 

(1 94H), and Pohl (1 980). In all of these Hornolepis 

is distinguisl~ed from Panicurn by the long loiver 

glume, noti-inctui.ate ~ipper antheciuni, and thin, 

flat niargins of’ the upper lenima. These criteria 

i$.ei.e also used 11:. Pilger in 19.34, but Hsu in his 

1965 studv of‘ the Paniceae made no mention of 

tlie genus. 

0111- st utlies Iiave shown that two additional 

species of Panicurn, P. glutinosurn and P. villaricense, shai-e the generic characters of Hornolepis 

and should be transfei-red to it, bringing to five 

tlie nunibei- of species in this American genus. 

Tlie forniei. beconies tlie most \$.idel? distributed 

menibei-, occurring from Mexico and the M’est 

I ndies to Argeiitiiia. Hornolepis isocalyia is found 

in liexico (iv1ie1.e only the type of one of its 

s~~non~~nis, Panicurn langei, has been collected), 

Rinaina, atid South America, ivhile H. aturensis 

ranges fi-oni hiexico to Bolivia and Brazil. T~vo 

species are know^ otil>. fiorn South America: H. 

longispiczclu is endeniic to the cerrados of Brazil 

and H. uillaricensis is restricted to Paraguay, Argentina, and southern BI 

New features, as revealed by SEM studies, 

~OTTO~OTJ t e the previous separation of Pa nicurn 

and Hornolepis that ivas based on characters of 

the spikelet, flo\\.er, and fruit. The major differences bet\\.een these genera ai-e summarized in 

the follo\ving paragmphs. 

Spikelet: The lo~,er and upper glumes in 

Hornolepis are similar, equal in length and not 

differing iii their morphology, and the margins 

of all bracts are o\,erlapping. The length of the 

Io~.er glunie in Panicurn varies from ]/r, to Y4 that 

of the spikelet, not equalling it nor the upper 

glunie. In 21 feiv species, where the lower glume 

is more de\.eloped, it differs from the upper in 

such features as type of apex, nei 

pubescence. This occurs in Panicurn obtusurn, P. 

longipedicellaturn, and in species of the Pat-vifolia 

group, for example. M’ith feiv exceptions, the 

upper antheciuni is indurate in Panicurn and the 

margins of the ~ippei- lemnia are inrolled over 

the palea (Figure 12). In Hornolepis the upper 

antheciuni is ch;ii.taceous and the m;irgins of the 

lemma ai-e flat and not ini.olled over the palea 

(Figure 9). The lo\z.er lemina of Hornolepis noi’- 

mallv exhibits differing degrees and types of 

pubescence, ivliile tlie glunies are glabi.ous (pilose 

up to the margins in H. aturensis and H. longispicula). C:on\.ersely, \%.lien the spikelet is pubescent in Panicurn, the hairs occur on both glumes 

and inore sparsely over the loiver lemnia. 

The hiluni of Hornolepis is linear, a 

chai.acter that clearly distinguishes it froni Panicum, in \$.Iiicli this structure is punctifoim or 

rarely oblong. il’hile linear in H. glutinosa and 

H. viilaricensis it is sonieF\.hat broadei- and occupies half or ;I little inore tlie length of the caryopsis. Chase niade no mention of the caryopsis 

in her desct-iptioii of the genus. 

The presence of a particular type 

of silica cell in the epideimis of the upper antheciuin is ;I peviously unrecorded charactel- that 

further differentiates the t\vo genera. Such silica 

cells in Hornolepis are dumbbell-shaped and alike 

in all species. Silica cells also occur toivard the 

tip of the upper antheciuni in certain species of 

the Imi-ea and Lisa groups of Panicurn but are 

rare, randonil>, disposed, and niai.kedly different 

from those in Hornolepis. 

The 1iteratui.e contains relativel!. few studies 

concerned \zit11 the surface of glunies and antheciurn, among these Baum (1 97 l), Baum and Hadland (1 973), Clark and Gould (1 97.i), Thoniasson (1 97Xa,b), Shaw and Seims (1 gig), SIiaFv and 

Webster (1 98 l), and Tei-rell and M’ergin (1 979, 

198 1). Clark and Gould (1 973) utilized differen tial chai-ac ters of the ant heci ii ni s LI r face to 

separate Ilichantheliurn from Panicurn, pointing 

out that the upper palea in the former is covered 

evenly \$.it11 simple papillae, rvliile in the latter 

they do not occur or are cro.tvded together and 

distributed at randoni. Terrell and \Vergin 

(198 1) studied silica cells present on the surface 

Carjopsis: 

Silica Cells: 
14 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

of the pistillate lemmas in Zizania, showing that 

the four species of the genus could be separated 

by the different types of silica cells present in 

each. 

Chromosome ‘Yumbers: Gould and Soderstrom 

(1970) reported the first counts for the genus 

\\.it11 211 = 40 for H. isocalyia and 211 = 22 for 

H. aturensis, although Pohl and Davidse (1971) 

and Davidse and Pohl (1978) found the latter to 

be 211 = 20, concluding that the genus has a basic 

number of x = 10. These authors have also 

reported counts for H. glutinosa (as Panicurn glutinosurn) in their papers of 1971, 1972, 1974, 

and 1978. The most common basic number in 

Panicum is x = 9, although x = 10 occurs in 

species of the Laxa and Mertensia groups. 

H. glutinosa is a nonKranz or G4 species according to the data given 

by Bro\zn (1 977) under Panicum glutinosum. 

Broivn also listed Homolepsis aturensis and H. 

isocalyia ;is C:3 s?ecies. 

Leafblade Anatomy 

Hornolepis Chase, 1911, emended Zuloaga 8c 

Soderstrom 

Hornolepis Ch‘ise, 1 9 1 1 : 146. 

Plants perennial, stoloniferous or creeping, decumbent and rooting at the loizer nodes, then 

becoming erect, rarel) cespitose. Spikelets shortto long-pedicellate, arranged in lax panicles. 

Spikelets lanceolate to long-ellipsoid or obovoid, blunt or ivith an acute or acuminate apex, 

greenish or brown, compressed dorsiventrally, 

articulated below the glumes; glumes subequal 

or the lolvei. somewhat larger than the upper, 

completely covering the lower lemma and upper 

anthecium or occasionally leaving exposed the 

summit of both anthecia. Lower glume 5-9- 

nerved, glabrous, its margins enclosing the upper. Llpper glume 7-9-nerved, commonly glabrous, its margins enclosing the lower lemnia. 

Lower lemma glume-like, 5-7-nerved, pilose, its 

margins broadly enclosing the upper antheciurn. 

Louier palea membranous, often equal in size to 

its lemma and conspicuous; r-nale flower sonietimes present. Lpper anthecium ellipsoid, chartaceous, compressed dorsiventrally, acute or acuminate, glabrous (sometimes with bicellular rnicrohairs or hooks toward the apex), pale, covered 

rvith suborbicular silica cells evenly distributed 

over the lenima and palea; lemma with flat margins, not inrolled over the palea and enclosing 

the greater part of it; palea of similar texture; 

lodicules 2, conduplicate; anthers 3; stigmas 2, 

plumose. Caryopsis obovoid to oblong, broivn, 

with a linear hilum and embryo more or less half 

its length. 

An exclusiirely American genus kvith species 

occupying huiiiid habitats and shady places in 

forests or woods from Mexico to Bolivia, Brazil, 

Paraguay, and Argentina, with one species endemic to the cerrados of Brazil. 

TYPE-SPECIES.-panicum aturense H.B.K. 

Key to the Species of Hornolepis 

Spikelets 9-1 1 mm long, 2-2.9 mm wide; glumes and lower lemma pubescent, lower lemma 

with long submarginal hairs; lower palea conspicuous, as long as its lemma; male flower present; 

plants cespitose with the culms few-noded, erect, not branching; ligule ciliate; sheaths keeled, 

rigid; blades linear-lanceolate, rigid, involute, 0.2-0.6 cm wide. Cerrados in the north of Brazil 

.............................................................. H.longispicula 

Spikelets 2.7-8 inn1 long, 1-1.8 mm \\side; upper glume usually glabrous, lower lemma sparsely 

pube3cent; louer palea small, never equal in size to the lemma; male flower rarely present; plants 

stoloniferous to decumbent, rooting and branching at the lower nodes; ligule membranous to 

membi-anous-ciliate; sheaths rounded, herbaceous; blades oblong-lanceolate to ovate-lanceolate, 

flat, 0.6-2.3 cm wide. Inhabiting forests or woods, never in cerrados . . . . . . . . . . . . . . . . . . .2 
NUMBER 59 15 

2. Spikelets 2.7-3.7 mni long; lower lemma without thick hairs in the central part: caryopsis 

Mith a broadened linear hilum half or a little more than half as long as the carvopsis; upper 

3. Panicle 12-25 cm long, 7-22 cm wide, with the lower branching verticillate; plants 

robust, 0.6- 1.8 111 tall; blades 10-43 cm long, 0.6-2.3 cm wide .................. 

3. Panicle 5-1 1 cm long, 1.5-5 cm wide, with opposite or alternate branches, not 

verticillate; plants small, 0.2-0.4 m tall: blades 4-12 cm long, 0.6-0.9 cm wide ...... 

Spikelets 4.6-8 mni long: lower lemma with thick hairs in the central part; caryopsis with a 

narro\<, linear hilum as long as the caryopsis; upper anthecium glabrous. ............ .4 

4. Spikelets ellipsoid, acute, 4.6-7.5 mm long; lower lemma sparsely pubescent between 

the lateral nerves arid with thick hairs on the middle part or glabrescent; upper 

anthecium acute, chartaceous .................................. H. isocaljcia 

Spikelets lanceolate, acuminate, 6.2-8 mm long; lower lemma densely pubescent between the lateral nerves and with thick papillose-pilose hairs up to the apex of the 

middle and toward the sides; upper anthecium acuminate, thin, of weak consistency . . ......................................................... H.aturensis 

anthecium scabrous at the apex ............................................ .3 

........................................... H. glutinosa, new combination 

........................................ H. villaricensis, new combination 

2. 

4. 

Hornolepis aturensis (H.B.K.) Chase 

FIGURE 6 

Hornolepis aturensis (H.B.K.) Chase, 191 1:146. 

Panicurn aturense Huniboldt, Bonpland, and Kunth, 

1816: 103, pl. 33. [Type: "Crescit ad cataractas Aturensis." Holotype, P, not seen; fragment of the type, US sheet 

Panicurn nzridzjlorurn Nees, 1829: 135. [Type: "Habitat in 

herbario nostro occurrit, nesco nunde illatum." Type not 

Ioca ted. ] 

Panicurn blepharoporum J.S. Presl in K.B. Presl, 1830:312. 

[Type: "Habitat in Mexico." Holotype, PR, not seen; 

fragmenr of the type3 US sheet no. 80486.1 

Panicurn turnescens Tr.inius, 1834:s 16. [Type: "V. spp. Bras." 

Holotype, LE, not seen; isotype, NY; fragment of the 

type, US sheet no. 81 158.1 

Stoloniferous perennials, 20-60 ciii tall. Culms 

compressed, glabrous, erect or geniculate-ascending and rooting at the lokver nodes, the 

internodes hello\<., 2- 1 1 cni long. lYodes brown, 

con i pressed, g I a b 1-o us or 1%. it h 1 on g 1%. hit i s h hairs . 

Sheaths ?-7 ciii long, the margins pilose with thin 

r\.hitish hairs, glabrous over the rest of the surf'xe 01- I~;ipillose-pilose: collar broLvn, pubescent 

to glabrous. Ligule niembranous, short-ciliate on 

110. 80.535.1 

the upper part, 0.3-0.6 mm long. Blades oblonglanceolate, acuminate, 6-1 2 cm long, 0.7-1.5 cni 

\vide, flat, i<.ith a short pseudopetiole, the base 

cordate, the njargins ciliate or scabrous, \vith 

strigose pubescence on both surfaces or glabrous, 

tessellate. Panicles lax, ellipsoid, 3.5-9 cni long, 

1-4 cm \vide, the branches shortly divergent 

from the axis lvith the spikelets congested along 

the branches; axis glabrous, smooth, undulate, 

the branches alternating, infrequently opposite, 

glabrous, the axils glabrous. Spikelets fusoid, acuminate, 6.2-8 nim long, 1.3- 1.8 tnni !vide, 

greenish to pale, herbaceous, strongly conipressed dorsiventrally, glunles and loiver- leninia 

faintly nerved. Lower glume acuminate, as long as 

the spikelet, enclosing part of the the upper 

glume, 5-9-net-ved, glabi-ow. Cyper glume 7-9- 

nerved, frequently tessellate, short- to long-pubescent betLveen the lateral nerves in the zone 

covered by the loi$.ei. glunie, the hairs delicate, 

the rest of the surface glabrous. Louler lemma 

glume-like, 7-nerved, densely pubescent betlveen 

the lateral nerves, the hairs purplish and whitish, 

the central nerves inconspicuous, ivith thick tuberculate hairs in the middle and oblong bicellular 
16 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE ri.--Homolepis aturensis: a, upper anthecium, lemma side (X 500); b, detail of upper 

palea shoi\.ing a suborbicular silica cell (X 5000); c, lower lemma showing base of a macrohair 

(X .iOO); d, lower lemma showing macrohairs (X 100). Photomicrographs a and b based on 

Arrher 1426 (CS), c and d on Prance 2860 (US). 
NUMBER 59 17 

microhairs. Lower palea lanceolate, 2-3.2 mm 

long, 0.5-0.9 nini wide, whitish, hyaline, glabrous; male flower rarely present. Upper anthecium ellipsoid, acuminate, 4.6-5.3 mm long, 1.1- 

1.4 mm wide, glabrous, pale to whitish, herbaceous, with silica cells distributed evenly, the 

lemma 5-nerved, its wide margins enclosing the 

palea. Caryopsis broadly obovoid, 2.5 mm long, 

1.3 mm wide, brown, with a linear hilum, as long 

as the caryopsis; embryo less than half the length 

of the caryopsis. 

DIsTRrBuTIoN.-~idely distributed from 

Mexico to Bolivia and northern Brazil. Found 

commonly in margins of forests or woods or in 

open inundated or swampy places and along the 

margins of rivers in wet and sandy soils. This 

species, which occurs from sea level to 1700 

meters elevation, has been reported as a weed of 

plantations in Brazil. 

ADDITIONAL SPECIMENSEEN.-BELIZE. EL 

CAYO: Central Farm, Reyes 4 (US); Cohune 

Ridge, Lundell 6425 (US); Augustine, Mountain 

Pine Ridge, Hunt 101 (US); Cay0 Road, Gentle 

9704 (US). STANN CREEK: near. Stann Creek 

town, Gentle 9097 (US); Stann Creek, Schipp 896 

(NY, US). TOLEDO: Punta Gorda-Cero Road, 

Gentle 6835 (US); edge of pineland, condemned 

Branch Pine Ridge, Gentle 7752 (US); in sacatal, 

near Machaca, Gentle 6891 (US); between cattle 

landing and Rio Grande, Gentle 6879 (US); Gracie Rock, Sibun River, Gentle 1629 (NY, US); 

Temash river, Schipp 1373 (NY, -US); Masons 

Lease, Smart 54 (US); Little Cocquericot, Belize 

river, Lundell 3878 (US). 

BOLIVIA. BENI: Guayamerin, Krapouickas €3 

Schinini 35109 (US). SANTA CRUZ: Buena Vista, 

Ste3nnbach 1844 (NY), 5120 (US). 

BRAZIL. ACRE: Cruzeiro do Sul, road Cruzeiro do Sul-Japini, Prance et al. 2860 (US). AMAZONAS: Barcelos, Negro river, Baldwin 3330 

(US); Icana river, Santa Ana, Froes 28472 (US); 

Japura river, Rodrigues 620 (US); 30-50 km from 

Manaus, along the Manaus-Itacoatiara road, Eiten €3 Eiten 5267 (US); Manaus, km 8 da BR 17, 

Rodrigues €3 Chagas 3083 (US); Manaus, rua Duque de Caxias, Rodrigues €3 Coelho 3076 (US); 

Moura, Negro river, Baldwin 3365 (US); Reserva 

Fiorestdl Ducke, km 26, Prance et al. 2627 (US); 

Santa Isabel, Negro river, Baldwin 3457 (US). 

GOIAS:Rio Doce, 65 km W of Rio Verde, Chase 

11727 (US); W of Rio Verde, Chase 12072 (NY, 

US). MARANHAO: Barra do Corda to Grajau, 

Swallen 3670 (US); kni 427, margens da Rod. 

BR-316, Rosa €3 Vilar 3136 (NY). PARA:Belem, 

Kuhlmann s.n., 13 Aug 1923 (US); Braganga 

railroad, Goeldi 43 (NY, US); Castanha, Fazenda 

Setenta-dois, Mexia 5909 (US); Lagoa Agua 

Preta, Drouet 2028 (NY, US); Mosqueira, Swallen 

4891 €3 1/2(US); Santarem, Spruce 30 (NY, US), 

765 (US); 36 kni SE of Vigia, Dauidse et al. 17591 

(NY). PERNAMBUCO: Dois Irmaos, vicinity of Recife, Chase 7725 (US); Recife, Pickel 3608 (US). 

COLOMBIA. Angelopolis, vicinity of Medellin, Taro 270 (NY, US); Bnenaventura, Hitchcock 

19905 (US); vicinity of MedelIiA, Toro 474 (NY, 

US); Santa Marta, Smith 170 (NY, US). AMAZONAS: about 6 kin N of Leticia at Santa Isabel, 

Gillett €3 Dickenson 16520 (US); Loretoyacu river, 

Schultes 6015 (US). ANTIOQUIA: Puerto Berrio, 

Juzepcruk 4862 (US); Santa Catalina, Bosse 3670 

(US); Venecia, granja de las Mercedes, Gutierrer 

CY Barkley s.n. (US 2184160). CAUCA: Chisquio, 

Finca Los Derrumbos, Asplund 10558 (US); C6rdoba, Dagua valley, Pittier 560 (US); El Tambo, 

Garcia Barriga 4416 (US); La Esmeralda, near 

Jamundi, Cauca valley, Pittier 936 (US); Rio Sucio, W of Popayan, Pennell €3 Killip 8163 (US). 

CHOCO: Atrato river, above Quibd6, Sabuidero, 

Cuatrecasas €3 Llano 24062 (US); Andagoya, Killip 35497 (US); Atrato river, near Quibd6, Molirta €3 Barkley s.n. (US 2206657); between La 

Oveja and Quibd6, Archer 1690 (US); Quibd6, 

quebrada la Platina, Idrobo €3 Cuatrecasas 2705 

(US); San Juan river, Cuatrecasas 21372 (US); 

Serrano river, Forero et al. 1371 (NY). EL VALLE: 

Rio Calima, Aguaclara, Cuatrecasas 21 167 (US); 

Alto del Dinde, between Cartago and Alcali, 

Cuatrecasas 22939 (US); Buenaventura, AsplCnd 

4984 (US); Buenaventura, Cbrdoba, Idrobo 6250 

(US); Cajambre river, Pacific coast, Cuatrecasas 

16955 (US); Calima river, Pacific coast, Cuatrecasas €3 Willard 26071 (US); Pacific coast, Yu- 
18 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

runiangui river, i’eneral, Cuatrecasas 15895 

(US); Isla del Guayabal, in the mouth of Cajambre ri\,er, Cuatrecasas 16222A (US); Naya 

river, Puerto \lei-izalde, Pacific coast, Cuatrecasas 14001 (US): Calima river, bettveen La Esperanm y Bellavista, Cuatrecasas 16796 (US). META: 

along Rio Ocoa, SE of Villavicencio, Kill$ 34371 

(US); i’illavicencio, Cuatrecasas 1973 (US), Pennell 1514 (US), Pe‘rez 5336 (US). SANTANDER: 

Granja Expel-iniental Agua Caliente, N of 

Plaron, Robinson Jr. 3010 (US); La Gomez, 40 

kni E of Puerto M‘ilches, Fosberg L3 Fassett 21 767 

(US); Puerto Wilches and vicinity, Killip 3 Smith 

14813 (NY, US). VAUPESIS~S: Rio GuainIa, Puerto 

Colombia and vicinity, Schultes et al. 18149 (US). 

COSTA R I (;A. CARTAGO: I nstit uto In teraiiieric;ino de Ciencias Agricolas, Turrialba, Davidse 935 (US); betr\.een Pavones y Charia, Turrialba, Jimenez 751 (KY). LIMONN: Hamburg 

Finca, on the Rio Keventazon below Cairo, Standlej 3 Valerio 48682 (US); 3 mi S of Puerto 

Limon, Lathrop 5542 (US); betlveen Rio Linion 

v Rio Banano,Jimeenez 2830 (NY); Rio Cimarron,

crossing of highivay, E of Siquirres, Pohl 13185 

(KY): v;ille).s of Sixaloa river, 2 km Mi of Barnbu, 

Pohl 3 Pinette 13198 (NY). PUNTARENAS: 0.5 krn 

\Y of Buenos :!ires, Pohl 3 Pinette 13262 (NY); 

Buenos Aires, Tondur 4876 (US). 

ECUADOR. ESMERALDES: Playa Rica, Parroquia de Concepcion, .Llexia 8946 (US); in clearings near Borbon, Jativa €3 Epling 2141 (NY). 

LOS RIos: Hacienda Sta. Lucia, canton Vinces, 

iblexia 6584 (US); Rio Palenque Biological Station, Dodson 5813 (US). KAPO-PASTAZA: Tena, 

Asplund 8954 (US). PICHINCHA: between Santo 

Domingo and Quininde, Acosta Solis 13694 (US). 

(; U A7’Ehl12 LIZ. ALTA VERAPAZ: Chama, 

Johnson 456 (US); Coban, von Tuerckheim 1255 

(SY, US), 3772 (US): Cubilquitz, uon Tuerckheim 

7698 (YY, US): E’inca Socuyo, SE of Carcha, 

Standlej 70285 (US); S of Cubilquitz, Steyermark 

44560 (US); vicinity of Secanquini, Pittier 248 

(US). IZARAI.: betM.een Bananera and La Presa, 

in Xlontania del >lice, Steyermark 38074 (US); 

Cristina, Blake 7598 (US); vicinity of Quirigua, 

Standlej 24017 (NY, US). PETEN: Dolores, km 

8.5, M’ of road, Contreras 2955 (US); Puerto 

Barrios, Brenckle 47-184 (KY), Hitchcock 9156-11 

2 (US); vicinitv of Puerto Barrios, Standley 24725, 

24978 (US). 

FRENCH GCIANA. CAYENNE: vicinity of 

Cayenne, Broadway 703 (NY, US). 

HONDURAS. CORTES: Yojoa Lake, Garcia 93 

(NY): Agua ilzul, on shores of Lake Yojoa, ,!lorton 7699 (US): Puerto Cortess, Carleton 623 (US); 

between Agua Azul y Pito Solo, ,Vlolina 5584 

(US). MORAZAN: near El Hombre river, NW of 

La Venta, Molina 13420 (US). GRACIAS A DIOS: 

along Platano river, Pohl €3 Gabel 13342 (NY). 

MEXICO. CHIAPAS: near the junction of the 

Rio Perlas and Rio Jatate at San Quintin and 

near Laguna Miramar, Sohns 1633 (US). OAXACA: Chiltepec, ,Zlartiner Calderon 721 (US), 981 

(NY); Comaltepeque, Galeotti 5859 (US); Santa 

Maria de Lovani, Vera Santos 3440 (NY, US); 1 

km S of i’alle Sacional, on the road to Sari 

hlateo, Rredowski 33792 (NY). TABASCO: Mayito, 

Rouirosa 425 (KY, US); Ocuapan, near Huirnanguiilo, Archer 3973 (US). i’ERACRUZ: along the 

Trans-Isthmian Highivay, 4 Km NE of Minatitah, King 1070 (US); El Palniar, Zongolica, Vera 

Santos 2304 (NY, US); Sabana Palenque, iblatuda 

3736 (US); Jicaltepec, Liebmann 391 (US). 

NICARAGUA. State unknown: La Tronquera, ,!lolina 14956 (NY); region of Braggnian’s 

Bluff, Englesing 295 (US); El Recreo, Semple 110 

(US). ZELAYA: field S of airport, Seill6485 (NY). 

PANAMA. BOCAS DEL TORO: Su’ of Bocas, 

Mlacatv Hills, von Il’edel 529 (US); Isla Colon, von 

Il’edel 2801 (US). CHIRIQUI:: CU~: Chiriqui Viejo river,

.ZlcCorkle 690 (NY); vicinity of El Boquete, Hitchcock 8352 (US). COLON: around Empire, Canal

Zone, Pittier 3727 (US); Barro Colorado Island, 

Fairchild Point, Ebinger 278 (US); Fort Sherni;iiin hlilitary Keservation, bettveen Chagres 

Batteries and Fort San Lorenzo, Canal Zone, 

.\.laxon 3 Valentine 703 1 (US); bet\\.een France 

Field and Catival, Standley 3039 (US); bettveen 

Corozal and Ancon, Canal Zone, Pittier 2635 

(US): bettveen Gorgona and Tabernilla, Canal 

Zone, Hitchcock 7963 (.US); between hlindi and 

Colom, Canal Zone, Hitchcock 7940 (US); Culebra, 
NCMRER 59 19 

Canal Zone, Hitchcock 7893 (US); Darien Station, 

Canal Zone, Standley 31558 (US); Ft. Kobbe, 

near beach, Duke 4181 (US); Juan Mina, Canal 

Zone, Piper 5268 (US): Gatun Lake, Goodyear, 

Seibert 1527 (US); Toro Point, Canal Zone, Hitchcock 8051 (US): jicinity of Fort Shermann, Canal 

Zone, Standley 30997’(US); vicinity of Summit, 

Chnal Zone, Standley 30071 (US); Canal Zone, 

Popenoe 14 (NY). DARIEN: Tuyra river, near the 

mouth of Rio Yape, Allen 332 (US). PANAMA: 

near ,2rraijam, IV’oodsonJr. 1379 (NY, US); Chorrera, Hitchcock 8129 (US): E of Orange river, 

(iormann 2572 (US): Tecumen, Duyer 2558 (US); 

‘I’ecumen river, Standley 26513 (US). VERAGUAS: 

road between Santiago & David, Stern et al. 1004 

(US); :Inchon Hill, Killip 4196 (US). 

PERU. CORONEL PORTILLO: environs of Pucalipa, 011 Ucayali river, Fosberg 28887 (NY). 

1.oRrro: Caballo-Cocha, on the Amazon river, 

Il‘illiams 2205 (US): lquitos, Anderson 1086 (US), 

..isplund 13922 (US), IV’illiarns 2964 (US); Maynas, Nanay river, Picuruyacu road below Bellavista, Rimachi 4816 (NY): lower Huallaga river, 

It‘illiams 4210 (US): lorver Nanay river, IVilliams 

262, 31 1 (US): Santa Maria, about 25 km below 

Yurimaguas 011 Rio Hiiallaga, Allard 22452 (US); 

\’aguas\.;icii river, Plowman et al. 6798 (US); Yuriniagua, outside of town, Anderson 254 (US), 

Ferrejra 10177 (US). 

\‘EWF.ZUElA. AMAZONAS: Alto Orinoco, Esnieralda savanna, Il‘illiams 15338 (US); El Temblador, Orinoco river betrveen San Antonio and 

Kirare, Foldats 256‘4 (US); Guainia river, just E 

of Xlaroa, ‘Llaguire et al. 41703 (US).TACHIRA:

Gi-aiija del FAado, San Cristobal, Tamayo 2294 

(LTS). TRU-JILLO: ]/4 mile from La Ceiba, Reed 932 

~:HROMOSOSIE NUMRERS.-~~ = 20 (Pohl and 

Davidse, 197 1): 211 = 22 (Gould and Soderstrom, 

1970): n = 10 (Davidse and Pohl, 1978). 

.., 

(US). 

Homolepis glutinosa (Swartz) Zuloaga & 

Soderstrom, new combination 

FIGURE 7 

Panicum glutinmum Sxvart7, 1788:24. [Type: “Jamaica.” 

Holotype, S. not seen; fragnients of the type, BAA, US 

sheet no. 80678.1 

Panicurn obtu5zjlorum Richard, 1853:305. [Type: “Crescit ad 

marginem rivuli Cauta in provincia Santiago de Cuba 

(Linden 11. 2143).” Holotype, P, not seen; fragment of the 

type, US sheet no. 80887.1 

Panicum lindenii Grisebach, 1866:233. [Based on Panicurn 

obtuszTorum Richard.] 

Robust perennials 0.6-1.2 111 tall. Culms decumbent, rooting and branching at the lower 

nodes, rarely stoloniferous, geniculate, cylindrical to compressed, pubescent (more so toward 

the upper part) to glabrous; internodes hollow, 

5-20 cm long. ,Yodes purplish, compressed, glabrous. Sheaths .5.5-18.4 cm long, generally 

shorter than the internodes, papillose-pilose to 

glabrescent. Ligule meinbranous, truncate, 0.1- 

0.3 mni long, lvith short hairs on the adaxial 

surface toivard the base of the blade; collar dark 

brown, densely pubescent kvith ivhitish hairs. 

Blades oblong-linear or lanceolate, 10-43 cm 

long, 0.6-2.3 cm rvide, flat, glaucous, distally 

attenuate, papillose-pilose 011 both surfaces to 

glabrescent, the margins scaberulous to papillosepilose belolv, the base narroLved, the midnerve 

prominent. Panicles lax, diffuse, many-flowered, 

exserted (included or not ivhen young in the 

upper leaves), 12-25 cm long, 7-22 ciii wide, 

the branches spreading, the spikelets separated 

on the branches: axis MY~VY and scaberulous, the 

loiver branghes in verticils, the upper alternate 

and opposite, the axils of the branches densely 

pubescent; pedicels scaberulous, 2-1 1 iiiiii long. 

Spikelets obovoid to ellipsoid, 2.7-3.5 inn1 long, 

1 - 1.6 miii \vide, greenish to olivaceous, viscous 

at maturity, the gliimes rvhitisli along the margins. Lozcer glume acute to obtuse, 2.4-3.1 mni 

long, 5-9-nerved, as long as or longer than the 

upper glunie, glabrous. Upper glume obtuse, 2.4- 

2.8 iiim long, 7-9-nerved, usually not enclosing 

the upper antheciuni, glabrous. Lower lemma 

glume-like, acute, 2.6-3.3 miii long, .5-7-nerved, 

slightly to markedly scabrous at the apex, covered ivith oblong bicellular microhairs, lvith the 

basal cell short and the upper cell elongated, 43- 

80 yni long, 11-22 ym wide. Lower palea ovatelanceolate, smaller than the lemina, 1.9-2.4 iiiiii 

long, 0.4-0..3 miii wide, membranous, glabrous; 
20 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 7.-Homolepis glutinosa, new combination: a, upper anthecium, lemma side (X 100); b, 

detail of a shotving dense aggregation of prickle hairs and bicellular microhairs (X 200); c, 

upper anthecium, palea side, showing the same as in b (X 200 ); d, detail of upper palea showing 

suborbicular silica cells (X 1000). All photomicrographs based on Eiten 3183. 
NUMBER 59 21 

inale flo~ver absent. C,-pper anthecium ellipsoid, 

2.5-3.3 nini long, 1-1.5 nini \vide, smooth, with 

iiunierous hooks and bicellular microhairs at the 

apex, shining, pale and Lvhitish, covered throughout by silica cells; anthers light broivn. Caryopsis 

rounded, 1 .7-2 iiiiii long, 1.3-1.8 mm \\ride, 

pale; hiluni linear, someivhat broad, half as long 

;IS the car!.opsis or ;I little longer; embryo half 

the length of the caryopsis. 

DISTRIRUTION.-~I~ forests of Mexico, Central 

llnierica, the M’est Indies, and South Anierica to 

Pai-agii;iy and :1rgentina; from sea level to 2500 

ni elevation. 

TI N,,l. (:oRRIt:Nms: arroyo Chimiray, Krapovickas et al. 25199 (CTES); arroyo Santa Isabel y 

ruta 12, Schinini 3 Quarin 8495 (CTES); deseniImcaduI-a ctel arroyo Garape en el Rioo Parani, 

4.5 kni k: de Ituzaingo, Schinini et al. 11089 

(CTES); Estancia Santa Teresa, Pedersen 2645 

(US); Kincon (>nibu Chico, Schinini et al. I1260 

((TES); Santa Ana, Carneuali 2365 (CTES); ruta 

40, 18 kin NE de Santo Tome, Krapovickas et al. 

25306 (CTES). ~IISIONES: Bernai-do de Irigoyen, 

Burkart 28255 (SI); Canipo i’iera, ,2Jontes 15364 

(SI); Fracrh, Parodi 5674 (BAA); Loreto, iVJontes 

1 I180 (LP); hlontecarlo, Montes 15397 (BAA), 

Porta 203 (BAlI), Schwindt 1329 (US); Parque 

(LP): Picada San \fartin, Schwarz 4486 (LIL); 

Puerto Ylani, Schwarz 10274 (LIL); San Pedro a 

Tobuna, Schziindt 4080 (US); San Pedro, Parodi 

5614 (Bi411); Santa Ana, Rodriguez 77 (MO, US). 

BOLIVIA. State unknown: Hacienda Siniaco, 

road to Tipuani, Buchtien 5316 (F, MO, SI, US); 

Mapiri, Rusbj 244 (US); San Carlos, Buchtien 23 

(BAA. CS). LA PAX: Coroico, De la Sota 454 

(€31114); %ongo valley, Renvoize 3 Cope 4251 

(\lo). SANTA (:RuZ: Buena i’ista, Steinbach 2015 

(SI), 14952 (US). 

BKAZI I,. M’ithout state and locality, bl’eddell 

1932 (NY). GOIAS: vicinity of Goiabeira, Chase vicinity of Goiabeira, Chase 

11496 (US). MINAS GERAIS: rvithout locality, 

Chase 9536 (US), Regnell III. 1370 (US), 12‘idgren 

912, 1299, 1845 (US), Campinas, Novaes 1247 

(US), Chase 9442 (US); Juiz de Fora, Chase 8570 

r~DDITTONAL. SPECIXlENS SEEN.-ARGESIL’, ‘ic : ional Iguasui, Cabrera, Gebhard J Corte 201 

(F, h40, NY, US); \.’icosa,Bailej 1011 (US), Kuhlmann s.n., 9 Xpr 193.5 (US). PARANA: without

locality, Dusen 3828 (US); Acungui, Mattos 3 

Labouriau s.n., 1 Mar 1948 (US); Carijo, Hatschbach 3040 (US); Curitiba, Swallen 8512 (US); 

Doce Fino, Hatschbach 401 1 (US); Fazenda Reserva, 85 km SW of Guarapuava, Lindeman et al. 

4692 (NY, US); Guarapuava, Swallen 8822 (US); 

Ponta Grossa, Swallen 8357 (US); Rio Espingarda, Hatschbach 4401 (US); Jaguariahyva, Dusen 1671 7 (MO, LS); Tres Barras, Dusen 17551 

(NY); Vossoreoca, Kummrov 318 (NY); Rio Lageado, Hatschbach 13745 (US); Rio Passa Dois, 

Hatschbach 15990 (US); Fazenda Lagoa, Hatschbach 14259 (US). Rro GRANDE DO SUL: Porto 

Alegre, Facultade de Agronomia, Valls 2005 

(US); Quinta near Rio Grande do Sul, Malme 

1574 (US); Azevedo, near Cai, Rambo 41438 

(US); Estacao Guianuba, Rambo 40548 (US); Jacar;, Rambo 40950 (US); Morro Agudo, near 

Porto Alegre, Rambo 41040 (US); Pareci, near 

Montenegro, Rambo 52770 (US); Sao Leopoldo

Leopoldo, 

Rambo 36987 (US). RIO DE JANEIRO: Alto Macah;e Glaziou 18647 (F, US); Alta Boa Vista, 

Chase 121?6 (US); Alto da Serra, S of Petropolis, 

Chase 9791 (US); Petropolis, Chase 12178 (US); 

Tijuca, Brade s.n., 31 Mar 1929 (US), Smith 2 

Brade 2206 (US). SANTA CATARINA: 33kin SE: of 

Cacador, Smith 3 Klein 12189 (NY, US); If kni 

W of Canipo Alegre, Smith 2 Klein 12035 (NY, 

US); Campo IIlegre, Morro do Iquererim, Reitz 

3 Klein 6389 (US); Canela Gaucha, Sao Miguel 

do Oeste, Klein 5068 (US); Chapeco, Klein 5287 

(US); Ilha de Santa Catarina, Morro Itacorubi, 

Reitz 4582 (US), Smith 3 Reitz 6166 (US); Itajai, 

Praia Braba, Klein 374 (US); Serra dos Ilheus, 

Smith 3 Klein 16032 (US); 14 kin N of Abelardo 

Lu7, Smith 3 Klein 11437 (US); Papanduva, Picadas, km 18 1 da ERF, Reitz 3 Klein 12510 (US); 

Pinheiral, 11 km M’ of Cacador, Smith 3 Klein 

10911 (NY, US); Rio Cacador, Swallen 8246 

(US). SAo PAULO: i\.ithout locality, Esteri 9916, 

9918 (US); Cambucy, Chase I I158 (US); Fazenda 

Canchim, 8 km NE of Sao Carlos, Eiten et al. 

318? (MO, US); Estafao Florestal do Paraguaccu 

Paulista, Clayton 4558 (NY, US); Parque do Es- 
22 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

tado, 1 lim E of Salo Paulo, Fonseca 52 (MO, US); 

near Piedade, 124 km from S. Paulo, Smith 6324 

(US); Sao Paulo, 10 kni S of center of city, 

Sendufsky 339 (US). 

COLOMBIA. W’ithout locality, ‘lloritz 759 

(US). ANTIOQUIA: Hatillo, Daniel 417 (US); Venecia, Graiija de las Mercedes, Barkley 3 Gutierre: 1657 (NY, US). CALDAS: Salento, Killip et al. 

876 1 (US). CAECA: Chisquio, Finca 10s Derrumbos, Asplund 10561 (US); El Ranial to Rio Sucio, 

M’ of Popavan, Penizef et al. 8090 (US); El Tambo, 

Kjell von Sneidern 21 16 (F, US); Popayan, near 

Tunia, Arbelaez et al. 6326 (US). CHOCO: between

La Oveja and Quibdo, Archer 1680 (US). CUNEL I’ALLE: Cordillera Occidental, Pichinde, Cuatrecasas 18237 (US); Cordillera Occidental, a1 S 

de Las Brisas, Cuatrecasas 22644 (US); La 

Cumbre, Pennel 5165 (KY, US); La Manuelita, 

Palniira, Pennel et al. 6172a (US); Las Nieves, W 

of Cali, Kiffip et al. 39209 (US); Monte Frio, 

Yanaconas, Killip et al. 33852 (LS). HCILA: San 

Agustin, Daniel 4096 (US). MAGDALENA: Sierra 

ISewda de Sta. Marta, Barklej 3 Gutierrez 1874 

(US). TOLIMA: La Trinidad, Libano, Pennel3329 

(XI’, US); \.icinity of Medellin, Toro 1020 (NY). 

(:OSTA RICA. Without province: Cucasacha, 

Lankester 21 1 (US); Helechales del General, Pittier 12002 (US); ALAJEELA: Piedades, near San 

Ramon, Brenes 4477 (US); Rioo Jeulis de San Ramon, Brenes 22890 (NY); La Palma de San Ranion, Brenes 4477 (KY). CARTAGO: 2 km NE of 

Sari Cristobal, Interseccion Norte, Pohl 13253 

(NY); .i km E of Bajo Pacuare, along road, Pohl 

13148 (NY); Alto de la Estrella, Standley 39042 

(US). PCNTARENAS: Canias Gordas, Pittier 11017 

(US). SAN JosE: Santa Maria de Dota, Standley 

41582 (US). 

CUBA. U’ithout locality, Wright 757 (NY, US); 

Las Villas, Buenos Aires, Morton 4153 (Us). ORIENTE: Grdn Piedra, Shafer 9014 (NY, Us); s of 

Guaro, Hitchcock 23416 (US); La Bayamesa, crest 

of the Sierra Maestra, lLlorton 9282 (US); La 

Perla, Leon 3790 (NY, US); Rio Yao, W of Sierra 

hlaestra, Morton et al. 3489 (US); Sierra Maestra, 

Alto de Iberia, Ekman 8298 (US); crest of Sierra 

DINAMARCA: Fus>igdsuaa, Pennel 2697 (NY, Us). 

Kipe, ,Llorton 3 Acuna 3208 (US), Shafer 299? 

(NY). PINAR DEL RIO: Taco-Taco, Sierra de Los 

Organos, Morton 4389, 4484 (US). SANTA 

CLARA: banks of Yayabo river, Leon 3998 (US). 

ECUADOR. ARCHIPIELAGO DE COLON: Isla 

Santa Cruz, above Bella Vista, Wzggins C3 Porter 

644 (US); Mt. Crocker, Indefatigable Island, 

Howell 9224 (US). ORO: betM.een Portobelo and 

El Tambo, Hitchcock 21300 (US). SANTIAGO-ZAMORA: Macas, Asplund 1920 (NY). 

GUATEMALA. ALTA I’ERAPAan: Cobin,Johnson 29 (US). BAJA L’ERAP.4Z: Sierra de las hlinas, 

3 km SE of Purulha, IZ’illiams et al. 43168 (F, 

US). HUEHUETENANGO: bet\j.een Barillas and 

Cerro I’ictoria, Steyermark 49697 (US); Ixcan and 

Finca San Rafael, Sierra de 10s Cuchumatanes, 

Steyermark 49466 (F, US). QUEZALTENANGO: Retalhuleu, Koninck 236 (US). 

GUY.4NA. Kamana Falls, ,Ifaguire et al. 

45963~ (NY); U’aru-Waru creek, Pomeroon, 

Bartfett 8124 (US). 

HAITI. Without locality, Ekman 623 (US); 

vicinity of Furcy, Leonard 4337 (NY, US); vicinity 

of Marinelade, Leonard 8212 (US); north\%.ard 

from hlorne Jeffrard, Bartlett 17557 (US); 

Source-Rouille, hlassif de la Selle, Ekman 6827 

(US); Terre Froid, Holdridge 1760 (US). 

HOh’DUR,4S. EL PARAISO: Yuscaran Yuscaran mountain, Molina 613 (US). 

JAXlAIC.4. Without locality, Hart 792 (US); 

Arntully, Orcutt 2643, 31 10 (US); Cinchona, Harris 11264 (US), 11440, 11508 (MO, US), Hitchcock 9708 (US); Diablo Mt., Ridley 25, 38 (US), 

Alaxon 3 Kilfip 443 (US); Elvarton to hloneague, 

Hitchcock 945 1 (US); Go]-dontown, Hitchcock 

93216 (US); near Ipswich, Hitchcock 9627 (US); 

Mason River Savanna, Tt‘ of Kellits, Fosberg 

42773 (US); Neivport, Britton 3193 (US); Red 

Hills, St. Andre\\., Harris 11836 (MO, US); road 

to Salt Hill, Harris 11395 (US); vicinity of St. 

Helen’s Gap, St. Andrew, ,Llaxon 3 Killip 595 

(US): St. Thomas, Cuna Cum trail, lZfaxon 3 

Killip 185 (US); Troy, Harris 12607 (MO, US), 

Hitchcock 9785 (US), ;Ilaxon 2816 (US). 

MEXICO. Il’ithout state: Mirador, Mohr s.n., 

in 1857 (US). HIDALGO: Zacual[ti]pan, Purpus 
NUMBER 59 23 

2903 (US). CHIAPAS: Turubula, il'elson 3357 

(US). OAXACA: Hiiantla de Jimenez, Schultes et 

al. 185 (US); San Ildefonso de ITiIla Alta, Yetzelala, \'era Santos 3503 (MO, US). ORIZABA: San 

Cristobal, Bourgeau 3192 (US). PCERLA: 30 kni 

N of %ac;ipoaxtla, Koch 7724 (US). VERACRUZ: 

near Jalapa, Hitchcock s. n. (US); Zacualpin and 

Imiciiiitv, Purpus 2156 (US). 

I',.ZK:ZGU:ZY. Lt'ithout state: Alto Parana, Nacunday, Alontes 10949 (US); Asuncion, Jardin 

Bota'inico, Rojas 14546 (BAA); Caacupe, Insfran 

1087 (SI);Carapegua, Rojas Rojas 3400 (US); Carobeni 

Suevo, ixxid to Itape, Rosengurtt 5896 (LP); Isla 

?'ei.esa, Bertoni 4294 (LIL); Lago Ipacaray, Hassler 22544 (F, 110, US); Pedro Juan Caballero, 

Rojas 6690 (BAA); Pirareta, Schinini 12183 

(CTES): :Zpa Ki\.ei., Hassler 11449 (US); Sapucay, Hassler 13027 (US); Tacuru Pucu, Fiebrig 

6502 (BX;\); Puerto Bertoni, Rojas 8070 (BAA). 

PERU. AMAZONAS: 1-5 kni SE of Yambrasbamba, ll'urdack 1033 (US). HUAUCO: Pampa Pampa 

Hermosa, between Puente Durand 8c Exito, 

,\.lexia 824? (F, MO, US); Pampayacu, mouth of 

Rio Chinchao, ,blurbride 5101 (US). JUNIN: Pichis Pichis 

trail, Yapas, Killip & Smith 25389 (F, US). SAN 

MARTIN: Juan Juan Guerra-Mayo River, Anderson 

1096 (US); road between Tarnpoto and Juan 

Guerra, Anderson 1108 (US). 

I'UEKTO KICO. Alta de Bandera, E of Adjuntas. O'hase 6469 (US); Guavate, Liogier 9771 

(US); Alaricao Insular forest, Schubert 337 (US); 

hlai-icao, wad to Indiei-a Fria, Chase s.n., 1913- 

Oct-23 (US); \.icinity of hlaricao, Chase 6199, 

6250 (US); Mayaguei., Sintenis 357 (US); Sierra 

de Yabucos, Sintenis 2609 (US). 

DO\ll~I~~,~ZS REPUBLIC. AZCA: Cordillera 

(:enti.al, Sail Juan, Ekman 13431 (US). LA \.r~~~: 

vicinity of Constanza, Allard 16451, 16488 (US); 

Constanza, near Rio Grande, Jimenez 2129 (US); 

vicinity of Jarabacoa, Allard 14886, 14909 (US); 

1,a Cienaga, south bank of Rio Los Guanos, 

Gastony et al. 220 (US); Lonia Canipana, Allard 

28216<US). ~IONTE CRISTI: Lagunas de Cenobi, 

Valeur 54 (US): Las Cidras, Valeur 520 (US). 

\'ENE%U ELA. State unknown: trail from Sanchorqiii7 to Galpan, Pittier 9578 (US). ARAGUA: 

Alto de Choroni, Chardon 181 (US); road betiveen Choroni and Maracay, Pittier 23923 (US), 

Soderstrom 976 (US), Tamayo 1636 (US); Parque 

Nacional, Chase 12456 (US). BOLIVAR: Santa 

Teresita de Kavanayen, Steyermark 60529 (F, 

US). DISTRITO FEDERAL: on the old road to Caracas from La Guayra, Pittier 5910 (US); Cerros 

del Avila, Altos de Galipin, Pittier 8301, 9915 

(US); Cordillera Costanera, Junquito, Chase 

12432 (US): Hacienda Puerto La Cruz, Pittier 

8060 (US). IARA: betrveen La Escalera y Cubiro, 

Burandt jr et al. 0032V (US); near Sanare, Parque 

Yacamb;i, Smith 132917 (US). MIRANDA: La Providencia, Pittier 23762 (US); road froni Los Canales to El Encanto, Lasser 660 (US); hills above 

I,os Teques, Pittier 21247 (US). TACHIRA: La La 

hlulera, Tamayo 2302 (US). 

CHROMOSOME SUMRERS.--~I~ = 'LO (Davidse 

and Pohl, 197'La,b, 1974, 1978), 211 = 40 (Pohl 

and Ilajidse, 197 1). 

DrscvssIoN.-This species u'as not placed in 

any group b). Hitchcock and Chase in their publication of 19 10. 111 an unpublished manuscript 

Chase later included it in the group Glutinosa, 

along ivith P. millegrana and P. selloxlii, taxi to 

ivhich ive do not believe it to be related. 

Homolepis glutinosa and H. villaricensis were 

included in section Glutinosa of Panicum (Zuloaga, 1978) on the basis of glume length and by 

the type of pubescence in the spikelet. In both 

species the lolver and upper glunies reach about 

the same sire and developnient and are indistinguishable niorphologically; frequently the loiver 

glurne exceeds the upper in length. In relation 

to the spikelet the length of the glumes is variable, in certain cases enclosing the upper antheciuni entirely, in others leaving the apex exposed 

(especially on the dorsal face of the spikelet, as 

the upper glume is smaller). In young spikelets 

both glumes frequently enclose the anthecia entirely. In this state the spikelet is compressed 

dorsiventrally and its form is ellipsoid. U'hen the 

spikelets mature the upper antheciuni becomes 

more globose, exceeding both glurnes and the 

loiver lemma in length. 

The lemma in both species produces varying 
24 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

amounts of obovate to oblong bi- or tricellular 

secretory hairs. In H. glutinosa they are bicellular 

and oblong with the lower cell short and the 

upper elongated, rvhereas in H. villaricensis they 

are bi- or tricellular, globose, obovate, narrow at 

the base and globose toc\.ard the apex. The hairs 

contain a resin that is secreted when the spikelets 

mature and become dark brown. Although the 

resin is produced by the lower lemma, it exudes 

over the surface of the gluines and makes them 

viscous, for lvhich reason they usually become 

covered lvith foreign particles. Stant (1 973) referred to similar structures in Gibasis (Commelinaceae) as “glandular micro-hairs” and thought 

the distal cell, ivhich is distended and rounded, 

to be secretory. In the other three species, H. 

aturensis, H. isocalyia, and H. longispicula, the 

loiver lernma is pubescent with oblong bicellular 

hairs, similar to those present in H. glutinosa. 

These hairs also contain a substance that is dispersed 011 the glumes and loiver lemma. 

Scholz (1 978) mentions the presence of bicellular hairs ivith a distal globose cell on anthecia 

of various species of Panicum. Such hairs are 

indeed found on the anthecia of many species, 

particularly in the Parvifolia group \%.here their 

occurrence is u 11 i\.ersal. 

Pohl (1 980) indicated that the majority of the 

spikelets of Panicum glutinosum appeared to be 

cleistogamous in the specimens he observed from 

Costa Rica. He noted the characteristic viscosity 

of the “glumes” and felt the species Jvas unrelated 

to any other species of the genus that he Ivas 

treat i rI g . 

Hornolepis isocalycia (Meyer) Chase 

FrCURE 8 

Hornolepis isocaljcia (Meyer) Chase, 19 1 1: 146. 

Panicum isocaljcium Meyer, 18 18:39. [Type: “In arenosis 

unibrosis continentis.” Holotype, LE, not seen; fragment 

of the type, US sheet no. 80709.1 

Panicum oljrachne Beurling, 1834: 1 12. [Type: “Portobello 

KO. 24 1. In palmetis.” Type not located.] 

Panicum renggeri Steudel, 1853:89. [Type: “Paraguay. 

Bahia.“ Holotype, P, not seen; fragment of the the type, 

US sheet no. 2903503.1 

Panicum langei Fournier, 1886:23. [Type: “Teotalcingo 

(Liebmann n. 435. junio).” Holotype, C, not seen: fragment 

of the type, L‘S sheet no. 80730.1 

Perennials 50-100 cm tall. Culms firm, manynoded, stoloniferous or decumbent and branching and rooting at the lower nodes to cespitose, 

sparsely pilose to glabrous; internodes hollow, 5- 

9 cm long. Sodes brown, compressed, sparsely 

pilose to glabrous. Sheaths 5-8 cm long, prominently distichous, overlapping, papillose-pilose to 

glabrous, pubescent on the margins. Ligule membranous, ciliate, 0.3-0.4 inn1 long; collar brown, 

densely short-pubescent. Blades lanceolate to 

ovate-lanceolate, acuminate, 7-23 cm long, 1- 

1.8 cm wide, flat, greenish, pseudopetiolate, the 

base subcordate to cordate, the margins ciliate, 

the lower lvith long whitish hairs, tessellate, with 

long whitish hairs toward the base of the adaxial 

surface to densely pilose on both surfaces. Panicles lax, diffuse, sparse, 6-13 cm long, 1.5-5 cm 

Ivide, the branches spreading; axis cylindrical, 

glabrous, the branches alternate, the axils pilose. 

Spikelets broadly ellipsoid, 4.6-7.4 mm long, 1.6- 

2.1 mm vide, greenish, the glumes and lower 

lemma herbaceous kvith manifest nerves. Lower 

glume acute to acuminate, about as long as the 

spikelet, j-g-nerved Mith transverse veinlets or 

not, glabrous on both surfaces or lvith the inner 

surface scabrous. Upper glume acute to acuniinate, as long as the spikelet, 5-9-nerved, acute 

to acuminate, glabrous. Lower lemma glume-like, 

acute to acuminate, 5-7-nerved, sparsely pubescent on the outer surface to\v,ard the apex and 

upper margins, Ivith oblong bicellular microhairs 

and sometimes \\.ith long, thin, whitish hairs betrveen the t\z~o lateral nerves toward the apex, 

scabrous toward the apex of the inner surface. 

Lower palea lanceolate, 3.5-4 mm long, 0.5-0.8 

nini tvide, hyaline, transparent, glabrous; male 

flower rarely present. Upper anthecium ellipsoid, 

acute, 3.9-4.8 mm long, 1.1-1.6 mm \tide, pale, 

glabrous, \vith hooks and bicellular microhairs at 

the apex of the palea, the lemma and palea 

covered ivith evenly distributed silica cells; 

lemma .?-nerved. Carjopsis obovoid, 2.5 mm 
NUMBER 59 

FIGURE 8.--Homolepis isocalycia: a, upper anthecium, lemma side (X 100); b, detail of upper 

palea showing suborbicular silica cells (X 500); c, detail of lower lemma showing bicellular 

microhairs and prickle hairs (X 430); d, detail of upper anthecium, palea side, showing bicellular 

niicrohair and silica cells (X 1000). All photomicrographs based on Duarte 6092 (US). 

25 
26 

long, 1.3 iiim !vide, bi-olvn; Iiilum linear, as long 

;IS the caryopsis, embryo ‘h as long as the caryopsis. 

DISTRIBUTION.--~I~ moist and shaded woodlands or forests from Mexico and Panama to 

iiorthern Brazil. 

IZDDITIONAI. SPECIMENS SEEN.-BRAZIL. 

BAHIA: near Bahia, Salzmann s.n. (US); Bahia, 

Dorsett 3 Popenoe 4446 (US); de Brejao a Mucuge, Lemos Froes 19982 (US); Parafuso, 39 km 

NE: of Bahia. Chase 7976 (MO, US); Campo Santo 

to Bahia, Chase 8048 (MO, US); 40 kni S of 

Eunapolis, Porto Seguro, Arruda 1 (MO); 5 km 

SE: of Feira de Santana, Davidse et al. I1702 

(h1O); Serra do Rio de Contas, 11 km S of Rio 

de Contas on side road to LV of the road to 

I,i\wmento do Brunlado, Harley et al. 15077 

(US), 12-14 km K of toivn of Rio de Contas on 

the road to Slato Grosso, Harlej et al. 15179 

(VS): Serra do Sincorai, 9 km SIZ’ of Mucuge. on 

I-oad from Cascavel by the Rio Paraguacu, Harley 

et al. 15977 (US): 17.5 km N of Ubaitaba, near 

Sao ;lntonio de Jesus, on the BA 101 highr\.ay to 

Feira de Santaiia, Harley et al. 17033 (US), 5.6 

Liii N of SI~icug& on road to Andarai, Harley et 

al. I8880 (US), -10 km N of Barra de Estiva, on 

Ibicoara road, by the Rio Preto, Harley et al. 

15862 (US), -6 km N of Barra da Estiva on 

Ibicoara road, Harley et al. 15543 (US); south 

part of peninsula, vicinity of Bahia, Chase 7858 

(110, US): Marau, a 3 km do Porto, Mori et al.

11390 (hlO); hlarau-Ubaitaba, 45-50 km E of 

Lbaitaba, iIlori et al. 11950 ($10); 34 krn E of 

Moi-ro do Chapeu, Davidse et al. et al. 11870 (MO); 

Porto Seguro, BR 5, km 18, Duarte 6092 (US); 

7’. de Fi-eitas, 12 kin r\; of Cachoeira, Chase 8076 

(US); Cruz das iZliiias, Pinto 124 (US); Serra da 

Agua de Rega, 27 km N of Seabra, Irwin et al. 

31010 (SY).CEARA: Camp o Grande, Swallen 

4518 (US). ~IINAS GERAIS: 10-15 kni da cidade, 

I’llagalhaies 14143 (US); 17 kni SW of the Minas 

Gel-ais-Bahia border, along highway, Davidse et 

al. 11615 (NY). PARA: Alto Quimina, Sampaio 

5784 (US); Igarape. das Borboledas, Sampaio 

5580 (US); Rio Para, Sampaio 5516 (US). PERNAMBUCO: Olinda, Pickel 108 (US). RORAIMA: 

SMITHSONIAN CONTRIBUTIONS TO BOTANY 

plateau of Serra Tepequem, Prance et al. 4482 

COLOMBIA. ANTIOQUIA: Cisneros, Toro 

1027 (NY, US). SANTANDER: Mesa 10s Santos, S 

of Bucaramanga, Robinson Jr. 3181, 3195 (US). 

FRENCH GUIANA. Road Iracoubo-Organabo, kni :313, Black 3 *Muller 54-172393 (US); 

route de L‘ilcarouany, Hoock s.n., 1 1 hov 1955 

(NU). 

GUYAS,2. Il‘ithout locality, Jenman 6000 

(US): Kamakusa, upper Mazaruni river, De la 

Cruz 2251, 421 7 (110, NY, US); Wanalva river, 

De la Cruz 4057(NY, US); Bartica, Lengs.n. (NY, 

US): hiazaruni river, Bartlett 8059 (US); Kaieteur 

Fall, forest along left bank of Potaro river, Cowan 

3 Soderstrom 2002 (NY, US); vicinity of Penal 

settlement, on ryest side of Essequibo river, near 

mouth of 1lazaruni river, Hitchcock 17112 (NY, 

US); Il’aranar\.a Ranch, -3 mi from Jaca\va, Harrison 1097 (US): Kaiken, Paruima, Leakley 227 

(NY); Kaieteui- Plateau, .Iiaguire 3 Fanshawe 

23287 (NY): Xl:izai.uni river, Kalacoon, Archer 

2479 (US): Kartabo Point, at confluence of Cuyuni and hlazaruni rivers, Sandwith 644 (US). 

PilNrl1l~l. 1.5 miles S of Goofy Lake, Dzyer 

8027 (S10); Campo Tres, 3 mi NE Altos de 

Pacora, Liesner 528 (MO): Cerro Azul, Duyer s. n. 

(MO), Ebinger 405 (LIO), Godfrej 2047 (NY), 

Tjson 2132 (510): Cerro Jefe, Antonio 4701 

(h1O), Davidse 101 I6 (MO), Hammel 4814 (h1O); 

road to <;erro Jefe, 21 km N of Panamerican 

Highway, Folsom 3 Hartman 4620 (MO); road 

to Cerro Jefe, shore of Goofy Lake, Tl’itherspoon 

8439 (MO); road to Ceri-o Jefe, beyond Goofy 

Lake along road, Correa 3 Dressler 464 (MO); 

top of Cei-ro Jefe, Tyon et al. 441 1 (MO). 

SURIKAM. Kayser airstrip, 45 km above confluence with Lucie River, Irwin et al. 55980 (310, 

NY, US); Kaysei- airstrip, 25 km above confluence Ivith Luck River, ,\laguzre et al. 53956 (MO, 

hY, US); Sipalwini savanna, area on Brazilian 

frontier, Oldenburger et al. 355 (NY). 

\‘ENE%UELA. BOLIVAR: Hato Divina Pastora, 

Gran Sabana, a1 pie del cerro Ceita, Tamajo 2918 

(US); Icabaru-Santa Elena, 70 km NE of Icabaru, 

Croat 54228 (MO): Santa Elena, Tamayo 2780 

(410). 
NUMBER 59 27 

(US). TACHIoad from Palmira to Mulera, road from Palmira to Mulera, 

,Vfuller 889 (US). TRUJILLO: near Escuque, along 

road to \’alera, Pittier 13141 (MO, NY, US). 

DrscvssroN.-Although the species appears to 

be iiiost common in northern South America, 

the type specimen of one of its synonyms, Panicum langei, conies from Mexico. Curiously, we 

have no specimens from Central America, except 

recent collections from Panama. Steudel cited 

only “Paraguay. Bahia” for another synonym of 

this species, Panicum renggeri. Given the geographical distribution of H. isocalyia, we may 

assiiiiie there is an error in the labeling of the 

type material and that it was collected in the state 

of Bahia, Brazil. 

111 spikelet shape, pubescence, and consistency 

of the upper- arithecium, this species appears to 

be niost closely related to H. glutinosa and H. 

villaricensis. The upper anthecium in these three 

species is sonielvhat more rigid than in H. longispicula and H. aturensis. 

The lilbel dm of Irwin 55980 indicate that the 

culiiis of this species attain heights of 2.3 ni; data 

fi-om Chase 8076 indicate the plant has stolons 

reaching 3 iii 01- more in length. In this species 

there is great wi-iation in the size of the plants, 

paiiicles, and spikelets. The spikelets, for exaniple, range froin 4.6 to 7.4 mm in length, a 

\,ariation that does not correlate with other characters. There are examples of small plants Lvith 

spikelets 7 iiim or more long and robust plants 

\\.itli siiiallei. spikelets. For this reason kve consider it prudelit to maintain the material examined under ;I single species, H. isocalyia. 

HomoZepis longispicula (Doell) Chase 

FIGCRE 9

Hornolepis longispicula (Doell) Chase, 19 1 1 : 147. 

Panicum longtflorum Trinius, 1834:3 17, not Ginelin, 1796. 

[Tvpe: “Habitat in Brasilia, loco accuratis non adnotato 

(herb. Acad. Petropolit.). Holotype, LE, not seen; fragment of the liolotype, US sheet no. 80743.1 

Panicum longispirulurn Doell in Martius, 1877:26 1. [Type: 

the same :is that of Panicum longzjlorurn Trinius.] 

Ichnanthus longij7orus (Trinius) Bentham, 188 1: 145. 

Hornolepis longzyora (Trinius) Pilger, 1940:35. 

Cespitose perennials, shortly rhizoinatous, 40- 

90 cm tall. Culms few-noded, cylindrical, glabrous, erect, not branching, covered amply at 

the base by the sheaths; internodes hollow, 6-26 

cm long. ‘Vodes obscure, compressed, glabrous. 

Sheaths 6-2 1 cm long, the basal ones abbreviated, 

shorter than the lower internodes, the upper 

ones longer, pale, keeled, glabrous or papillosepilose to\<.ard the upper margins. Ligule a short 

arc, ciliate, formed by a line of \\.hitish hairs 0.3- 

0.6 mm long; collar glabrous or densely pubescent. Blades linear-lanceolate, subulate to acute, 

6-20 ciii long, 0.2-0.6 cni wide, rigid, narrow at 

the base, not clearly differentiated from the 

sheath, pubescent on both sides (more densely so 

on the abaxial side) to glabrous, the margins 

convolute, ciliate nith thin, fragile hairs, inidnerve prominent. Panicles contracted, exsei-ted, 

6-20 cm long, 1-7 cm wide, the branches appressed to the axis, the spikelets borne on long 

pedicels; axis cylindrical, undulate above, glabrous, smooth, purplish, the branches alternate 

or subopposite, smooth, glabrous, purplish, the 

pedicels claviform, 3-2.3 inn1 long, glabrous, 

smooth. Spikelets fusiform, 9- 1 1 inm long, 2-2.9 

nim \t.ide, acuniinate, greenish-violet, herbaceous, glunies and anthecia separated by distinct 

internodes. Louler glume acute, 9- 10 iiiiii long, 

greenish, .i-.l-nerved, glabrous or sparsely hirsute lzith caducous hairs. Cpper glume acuminate, 

8.2- 10 iiim long, .?-nerved, pubescent toiz,ard 

the margins, the hairs \vhitish and violet, the 

margins hyaline, the middle part hirsute, it,ith 

caducous tuberculate hairs. Lower lemma -8 inn1 

long, 3-7-nerved, densely pubescent (especially 

tolvard the niargins), the long hairs whitish and 

purplish with thick tubei-culate hairs on the middle part (more so to\zard the apex and margins) 

and oblong, hicellular microhairs. Lower palea 

conspicuous, lanceolate, 6-7 niiii long, 1 - 1 ..i 

mm \\.ide, as long as the lemma, hyaline, transparent, glabrous or pilose toizard the upper margins; male flou.er present lvith 3 stamens. C’pper 

anthecium fusifoim, 6.7-7.8 iiiiii long, 1.4-2 iiim 

ivide, herbaceous, rvhitish, glabrous or pubescent 

tolzard the upper- part, densely covered with 
28 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FICCRE F).-Homolepis longispicula: a, upper anthecium, palea side, showing flat margins of 

lemnia over palea and macrohairs on the lemma (X 100); b, lower lemma showing oblong 

bicellular niicrohair with collapsed upper cell (X 1400); c, upper palea showing suborbicular 

silica cells (X 1000); d, lower lemma with thick and thin macrohairs (X 80). Photomicrograph 

a based on Chase 10349 (US), b and d on Hatschbach 27965 (CS), and c on a fragment of the 

holotype (US). 
NUMBER 59 29 

silica cells throughout, the hyaline margins of the 

lemma enclosing almost entirely the palea. Caryopsis oblong, 2.9 mni long, l .5 mm wide, brown; 

hilum linear, as long as the caryopsis; embryo 

less than half as long as the caryopsis. 

DISTRIBUTION.-~n sandy soils of dry and 

open areas of the Brazilian cerrado in the states 

of GoiaS, Distrito Federal, and Minas Gerais, 

between 1000 and 1500 m elevation. Plants of 

this species are exposed to frequent fires as evidenced bj, the large number of herbarium specimens with burnt bases. 

ADDITIONAL SPECIMENS SEEN.-BRAZIL. 

DISTRITO FEDERAL: 10 km S of Brasilia on road 

to Belo Horizonte, Irwin et al. 8591 (MO, NY, 

US). GorAs: 2 kni NW of Veadeiros, road to 

Cavalcante, Irwin et al. 9489, 9491 (NY, US); 

vallev of Rio Corumba, Glaziou 22470 (US). 

MINAS GERAIS: Diamantina, summit of Serra de 

Sao Antonio, Chase 10349 (MO, NY, US); 5-10 

km W of Diairrantina, serra de Sao Antonio, 

Chase 10426 (US); Serra do Espinhaco, Hatschbach 27809 (NY, US); Serra do Cipo, along the 

road at km 134-135, Eden & Eiten 6750 (MO, 

US), 6754 (ISY, US); road BR 259, Hatschbach 

27965 (US); Serra do Cipo, 110 km NE of Belo 

Horizonte, Chase 921 I (MO, US). 

DrscussroN.-This species is clearly separable 

from others in the genus by its habit and habitat. 

The plants are cespitose with erect culms and 

densely covered at the base by hard, keeled 

sheaths that are resistant to fires. The blades are 

lanceolate, involute, rigid, and without a sharp 

differentiation between the sheath and the blade, 

and the ligule is ciliate, unlike that of the remaining species. The spikelet differs most notably in 

its conspicuous lower palea, which frequently 

encloses a well-developed male flower. In the 

remaining characters the spikelet conforms to 

the type common in the genus. 

Hornolepis villaricensis (Mez) Zuloaga 8c 

Soderstrom, new combination 

FIGURE 10 

Panicurn uillaricense Mez, 192 1 : 1. [Type: “Paraguay, Balansa 

n. 2.” Isotype, BAF; fragments of the type, BAA, US sheet 

no. 2808940.1 

Stoloniferous perennials 15-40 cm tall. Culms 

cylindrical or compressed, geniculate, branching 

at the lower nodes, glabrous; internodes hollow, 

1.5-1 1 cm long. Nodes glabrous, obscure. Sheaths 

shorter than the internodes, 2-8 cm long, the 

margins papillose-pilose to glabrescent. Lzgule 

membranous, laciniate, 0.4-0.8 mm long; collar 

dark brown, glabrous to pilose. Blades oblonglanceolate, acuminate, 4-1 2 cm long, 0.6-0.9 cm 

wide, flat, narrowed at the base, the margins 

scaberulous, the lower with caducous tuberculate 

hairs, strigose on both surfaces, the midnerve 

prominent. Panicles lax, diffuse, 5-1 1 cm long, 

1.5-5.5 cm wide, the axis scabrous, the lower 

branches alternate or opposite, the remaining 

ones alternate, the axils finely pubescent, pedicels scabrous, 3- 18 mm long. Spikelets ellipsoid 

to obovoid, 3.2-3.7 mm long, 1.2-1.5 mm wide, 

glabrous, dark green to olivaceous, viscous at 

maturity, the glumes usually enclosing the lower 

lemma and upper anthecium. Lower glume acute, 

3.1-3.4 mm long, as long as or longer than the 

upper glume, 5-9-nerved, glabrous. Upper glume 

acute, 2.9-3.4 mm long, 7-9-nerved, glabrous. 

Lower lemma glume-like, acute, 2.8-3.3 mm long, 

5-7-nerved, scabrous at the apex, the remainder 

of the surface densely covered with bi-, tri-, or 

(rarely) quadricellular microhairs, globose, obovoid, 40-70 pm long, 19-30 pm wide. Lower 

palea ovate-lanceolate, 1.9-2.4 mm long, 0.4- 

0.7 mm wide, membranous, hyaline, glabrous; 

male flower absent. Upper antheczum ellipsoid, 

2.8-3.2 mm long, 1.1-1.2 mm wide, smooth, 

shining, pale, covered with evenly distributed 

dumbbell-shaped silica cells, the apex of the 

lemma with numerous hooks and dense bicellular 

microhairs. Caryopsis obovoid, 1.8-2 nim long, 

1.4-1.8 mm wide; hilum linear, half as long as 

the caryopsis or a little longer; embryo half the 

length of the caryopsis. 

DISTRIBUTION. -southern Brazil, Paraguay, 

and northwestern Argentina, in shaded and humid habitats where it forms dense clumps beneath trees. 

ADDITIONAL SPECIMENS SEEN.-ARGENTINA. CORRIENTES: Garape stream, mouth of 

Parana River, 45 km E of Ituzaingo, Schinini et 
30 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 10.-Hornolepis uillaricensis, new combination: a, upper anthecium, lemma side (X 100); 

b, detail of a showing prickle hairs, bicellular microhairs, and suborbicular silica cells (X 300); 

c, upper anthecium, palea side, showing macrohairs, bicellular microhairs, and suborbicular 

silica cells (X 200); d, lower lemma, showing glandular microhairs, mostly collapsed (X 140). 

Photomicrographs a-c based on Rojas 3410 (US), and d on Schwindt 3266 (US). 
NUMBER 59 31 

al. 11096 (CTES), Quarin et al. 3375 (CTES); 

Estancia Santa Teresa, Pedersen 35 (US); Loreto, 

Ahumada @ Giberti 67 (SI, US). MISIONES: Loreto, Gruner 764 (BAA), Novat 78 (BAB); San 

Pedro, Parodi 5609 (BAA, US); Yabebyri, Montes 

747 (LP); San Ignacio, Giambiagio s.n., 1914 (SI 

13499), Quiroga s.n., 3 Apr 1914 (NY); San 

Antonio, Cabrera, Gebhard €3 Corte 108 (BAA); 

Campo Grande, Montes I5357 (SI, US); Salto 

Encantado, Schmidt 4555 (LIL); ruta 14, km 304, 

Schwindt 3266 (LIL, US); Teyucuare, Montes 

BRAZIL. PARANA: Guarapuava, Swallen 8909 

PARAGUAY. Villa Elisa, Pedersen 5902 (Pedersen, US); Villarica, Jorgensen 4094 (BAA, F, 

US), Ramirez 828 (BAA); Carobeni Nuevo, Rosengurtt 85895 (F, US); Carobeni Nuevo-Itape, 

Ramirez 676 (BAA); Ipacaray Lake, Hassler 

12469 (US), 12537 (MO); Alto Parana, niacunday, ,Llontes 10906 (US); Santiago, Estancia La 

Soledad, Pedersen 5948 (Pedersen, US); Alto Paraguay, Priniavera, Woolston 69 (SI); Asuncoh, 

Jardin Boakico, Rojas 12565 (BAA); Colonia 

Independencia, Rosengurtt 59?9 (BAA); Carapegua, Rojas 3410 (BL4A, US); Caaguazu, Hassler 

8919 (BAA, NY); Puerto Bertoni, Alto Parana, 

Rojas 7951 (BAA), Bertoni 3644 (US), 4701 (US); 

Tobati, Cerro Tobati, Arenas I145 (CTES), Hassler 500 (NY). 

DIscussroN.-Parodi (1 925) considered this 

species to be conspecific with Panicum glutinosum, 

believing that the smaller size of the plants was 

the result of logging and of trampling by cattle. 

2110 (US). 

(US). 

Zchnanthus 

Stieber, in his revision of Zchnanthus (1 982), 

divided the genus into two sections, Zchnanthus 

and Foveolatus, including in the first those species 

M ith prominent appendages attached to the base 

of the upper lemma and in the second those with 

scars at the base of the upper lemma. He noted 

that other authors (Zuloaga, 1981; Shaw and 

Webster, 1981) had demonstrated a common 

origin for appendages and scars. 

The size of the scars varies among the species 

in Foveolatus, from prominent as in Zchnanthus 

pallens to hardly apparent in I. camporum, I. 

minarum, and 1. procurrens. Stieber pointed out 

that the species in this section are further characterized by a dense aggregation of silica cells at 

the apex of the upper lemma. 

Our study of Panicum grandifolium has shown 

that a pair of diminutive scars is present at the 

base of the upper lemma, suggesting an alliance 

with species of Foveolatus. An SEM analysis of 

the upper anthecium has also revealed the presence of numerous silica cells at the summit of the 

upper palea and lemma, densely aggregated on 

the palea, sparser and more evenly arranged on 

the lemma. Additional characters that indicate a 

relationship to Zchnanthus include the keeled condition of the glumes and lateral compression of 

the spikelets. Because this species is so unlike any 

other within Panicum, instead sharing many characters with Zchnanthus, it seems appropriate to 

include it within this latter genus. Interestingly, 

Stieber (1 982) removed Zchnanthus nervosus from 

the genus and made it synonymous with Panicum 

grandifolium Doell. 

Zchnanthus grandifolius (Doell) Zuloaga 8c 

Soderstrom, new combination 

FIGURE 11 

Panicum grandijohm Doell in Martius, 1877:195. [Type: 

“Habitat in sylvis ad Itahypie fluviurn et Carnacorum vicum 

S. Pedro d’Alcantara provinciae Bahiensis (Martius).” 

Holotype, M, not seen; fragment of the type, US.] 

Ichnanthus neruosus Swallen, 1964: 147. [Type: “Brazil, Pernarnbuco, Tapera, in a woods, 24 Apr. 1935, Pickel 3855.” 

Holotype, US sheet no. 164517 12.1 

Cespitose perennials, 60-200 cni tall. Culms 

ascending, cylindrical to compressed, simple, 

short-pubescent below the nodes, otherwise glabrous; internodes solid, short at the base, becoming longer above, 7- 18 cm long. iVodes obscure, 

glabrous to short-pubescent. Sheaths 11-13 cm 

long, the lower ones longer than the internodes, 

the upper ones shorter, villous at the base and 

around the collar, the remaining sparsely pubes- 
32 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 1 1 .-Ichnanthus grandijolius, new combination: a, upper anthecium, lemma side (X 

100); b, detail of a showing silica cells and stoma (X 2000); c, upper anthecium, lemma side (X 

500); d, detail of upper palea (X 500). All photomicrographs based on Pickel 1629 (US). 
NUMBER 59 33 

cent to glabrous. Ligule nienibranous-ciliate, 0.7- 

1.1 iiim long, \\-it11 loiig hairs adaxially toward 

tlie base of the blade: collar dark broivii, glabrous 

to pubescent. Blades lanceolate, acuminate, 22- 

1 ciii long, 3..i-6 ciii \vide, flat, pseudopetiolate, 

\\.it11 ;in asyniiiietric apes and base, the lower 

111 argi ii s g la t1i.o 11 s to Ion g-p u bescen t , with thin , 

iion-tuhet.culate liaii-s, otherwise glabrous, the 

iiiidnewe proniiiient; pseudopetiole 0.3-2 cni 

long, short-pilose to glabrous. Panicles lax, 

essei-red, diffuse, pyi-aniidal, many-floivered, 

1.5-.50 ciii loiig, 5-1 4 cm \\.ide; axis angular, 

scabrous to liii-sute, the branches alternate to 

subopposite, diverging, triquetrous, the axils 

long-pilose, the spikelets in pairs and appressed 

along both sides of the branches, one subsessile, 

the other shortly pedicellate; pedicels scabrous 

to hirsute, claviform. Spikelets long-ellipsoid, 4- 

4..i inm long, 1-1.4 mni wide, greenish, shining, 

laterally compressed, pubescent only at the apex 

of the lorver glume, otherwise glabrous, glumes 

and IoM-ei- lemma rigid and with prominent 

nerves; upper glume and lower lemma subequal 

in length. Lowr glume ovate-lanceolate, acute, 

2.6-3.4 mm long, 2/i to V4 as long as the spikelet, 

its margins broadly enclosing the upper glume, 

3-nerved, the midnerve scabrous toward the 

apex and M.ith thick long whitish hairs, scabrous 

at the apex of the inner surface. Upper glume 

acute, 3.7-4.4 mni long, 5-nerved, both midnerve and inner surface scabrous. Lower lemma 

glume-like, acute, 3.6-4.3 mm long, 5-nerved, 

scabrous on the inner surface, completely embracing the upper anthecium at the base. Lower 

palea lanceolate, 3.1-3.6 mm long, 0.6-1 mm 

wide, membranous, pubescent along the edges, 

otherwise glabrous; male flower usually present 

with 3 stamens, the anthers 1.6 mm long. Upper 

anthecium fusiform, 3.3-3.7 nim long, 1 mm 

wide, laterally compressed, smooth, shining, 

membranous, the lemma enclosing the palea with 

its i\.ide margins, the lemma and palea with numerous silica cells and stomata at the apex; silica 

cells rounded, lvith 2-4 sinuses, more or less 

e\.enly distributed over tlie upper lemma and 

densely so oii tlie apex of the palea; small scars 

present ;it tlie base of the antheciurn on both 

sides of the leniiiia. (;arjopsis not seen. 

300 111 elevatioii in eastern Brazil-from Permnibuco to Espii-ito Santo-in riioist places 

ivitliin or at tlie edges of 12.oodlands or forests. 

BAHIA:23 23 km [El of Ibirataia, on side road 

connecting Ivith BK-101, Fanenda Macedonia, 

Calderdn et al. 2362 (US); Fazenda Uruguayaiia 

and vicinitv, 8 kiii S of Saiita Cru% da i'itoria, 

Soderstrom et al. 2109 (US): 6 kni E of Ubaira 

city: Rio Jequirica, Calderon 3 Pinheiro 2249 

(US); rodo\.ia Itabuna-Urucuca, Belem 3 Aguiar 

1248 (US). EsPIRI~ro SANTO: Keserva Biologica 

de Sooretania, Soderstrom 3 Sucre 1894 (US). 

PERNAMRUCO: Saziii-e. da llata, .Lloraes 1103 

(US): Tapera, Pickel 1629, 1928, 2347, ?543, 

Drscvssrow.-The sheaths of one specimen, 

Soderstrom 3 Sucre 1894, are distinctive in theirpurplish mottling. 

DIsTRIRvTIo~.-~CcUl~rillg frolii sea level to 

A D D IT ION A I. SPECIMENS S I.: EN. - B K A Z I L . 

3545 (US). 

Taxonomic Position of Panicum aristellum 

In an uriedited key to South Aiiierican species 

of Panicum, Chase considered P. aristellum to 

have little I-elationship to any other species of the 

geniis, because of the presence of ;i\viis on both 

glumes. She placed it next to the only other 

species Ivith aivned glumes, Panicum najadum 

Hackel, Lvliich w.;is later transferred to Oplismenopsis najada bv Parodi. In fact, Chase later 

agreed Fvith other authors in regarding Panicum 

as a genus i\.itli unarvned glumes. :Ii\.ned glunies 

are, ho\vever, characteristic of several other panicoid genera, such as Chaetium, Echinochloa, and 

Oplismenus. 

The thin and membranous uppei- antheciuin 

of P. aristellum resembles that of Hqmenachne 

(Figure 13), lvliicti rvas described by Beauvois in 

18 12 in the follo\ving iiiaiiiier- (as translated from 

the Latin): 

Panicle simple, spiciform: branches dense. - Glunies 

unequal, herbaceous, acute: the lower much shorter than 

the upper. Lower anthecium sterile: Lower lemma acute, 

the palea very short, membranous, hyaline. Upper anthecium hermaphrodite: the lemma and palea membranous, 

acute. 
34 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 12.-Panicum species: a, upper anthecium of P. vaseyanum, palea side (X 100); b, upper 

anthecium of P. quadriglume, lemma side (X 200); c, base of upper anthecium of P. hispidifoliurn 

(X 100); d, upper anthecium of P. difffusum, palea side (X 200). Photomicrograph a based on 

Pringle 1415 (US), b on Chase 8897 (US), con Valerio Rodriguez 1981, and d on Eggers 76 (CS). 
NUMBER 59 

FIGVRE lJ.-Hymenachne species: a, upper anthecium of H. hemitoma showing the thin lemma 

and palea (X 200); b, detail of upper anthecium, palea side, of a showing bicellular microhairs 

and silica cells (X 1000); c, detail of upper anthecium of H. amplexicaulis showing prickle hairs 

(X 1000); d, upper antheciuni of H. donacijolia (X 100). Photomicrographs a and b based on 

Tracy 8847 (US), c on Rosengurtt 6175 (US), and d on Ule 88? (US). 

35 
SMITHSONIAN CONTRIBUTIONS TO BOTANY 

Chase (1908) and later Pilger (1940, 1954) 

considered the distinguishing character of Hjmenachne to be the nieinbranous consistency of 

the upper leninia and palea, which is the basis of 

the generic iimie (hymen, membranous, plus 

achne, scale). In Panicum the upper antheciuni is 

comnionly indurate Mith the margins of the 

lemma inrolled over the palea (Figure 12). Chase 

included iii Hymenachne, H. amplexicaulis, a species !\.it11 spike-like panicles, and H. donacfolia, a 

species Ivith long and narrow panicles whose 

branches sometimes diverge from the axis. 

Panicum aristellum differs from Hq'menachne 

mainl?. iii the laxness of the panicle, the aristate 

condition of the glumes, and the presence of a 

plea and inale florver in the loiver- anthecium. 

Sonie species of the Laxa group of Panicum (P. 

pernambucense and P. grumosum) share ivith HJmenachne and P. aristellum a niembranous upper 

antheciuiii. In these species the spikelets are 

shoi-t-pec1icell;ite and foim dense racemes, which 

are 11ioi.e 01- less divergent from the axis and not 

much diffei-ent from H. donacfolia or H. condensata. In Hjmenachne and P. aristellum the glumes 

are acuiiiiiiate or aristate, whereas in the other 

species of Panicum cited above, the glumes and 

lo~ver lernnia are acute. The palea of the lower 

floret is usually absent in P. pernambucense but is 

present in P. grumosum. 

A similar habitat and geographical distribution 

are shared by Hjmenachne, P. aristellum, and the 

above species of Panicum. Panicum pernambucense 

occ~irs from Bahia to the north of Argentina and 

P. grumosum from Santa Catarina to the province 

of Buenos Ail-es, Argentina. ,411 of these species 

are chaixcteristic of ri\.er or lake margins and 

habitats periodically covered by rvater. 

Panicum, Panicum aristellum, and Hq'menachne 

ma\' be distinguished by the characters listed in 

Talle 2. 

If the consistency of the upper antheciuni is 

accepted as a character of generic importance to 

differentiate Hjmenachne froni Panicum, then 

Panicurn aristellum and species of the Laxa group 

~vould be congeneric \lit11 Hymenachne. In order 

to test this hypothesis, a study should be made of 

all of the species iii Hq'menachne as \\.ell as those 

of the Laxa group of Panicum. Because r3.e have 

not made such a study l+.e are not transferring P. 

aristellum to another genus at this time. 

Panicum 

Panicum aristellum Doell 

FIGURES 14, I3 

"Panicurn .-\riste//a" Doell in Rlartius, 1877:22 1. [Type: "In 

provincia hlinaruni a cl. M'idgren lectum (herb. Holm.)." 

Type, S, not seen; isotype, US sheet no. 702302; fragment 

of the tvpe, US sheet no. 80468.1 

Cespitose or shortly rhizoinatous perennials, 

1-2 111 tall. (;ulms erect, many-noded, simple, 

TARLL: 2.--Comparison of Panicurn, Panzcum arzstellum, and Hyrnenachne. 

Character I Panicum 

Panicum 

aristellum Hymenachne 

Upper anthecium 

Lower anthecium 

Glumes I and I1 

In florescence 

indurate or membranous, lemma covering the palea at the 

apex 

sent and sometimes 

a male flower 

palea present or abobtuse, acute or acuminate. not awned 

panicle lax to contracted 

membranous, lemma 

covering the palea 

at the apex 

palea and male flower 

present 

awned, the awns of 

equal length to the 

body of the glumes 

panicle lax, diffuse 

membranous, lemma 

not covering the palea at the apex 

palea and male flower 

absent 

acuminate, not aivned 

panicle spike-like to 

contracted 
NUMBER 59 37 

FIGURE 14.--Panicum aristellum: a, habit (X 1); b, panicle (X 1); c, branch of the panicle (X 12); 

d, ligule (X 3); e, scheme of sheath in cross section;f; lower glurne (X 25); g, upper glume (X 

25); h, upper anthecium, leninia side (X 25); i, upper anthecium, lateral view (X 25); j, upper 

antheciuni, palea side (X 25); k, stamens (X 25); 1, upper palea with gyneciurn and lodicules (X 

2.5); m, lodicules of the upper antheciurn (X 40); n, lower anthecium, lateral view (X 25); 0, 

lower anthecium, palea side (X 25). Drawing a based on Hatschbach 28413 (US), b-o on 

Hatschbach 28413 (US), Kuhlmann 2774 (US), and Widgren 924 (US). 
38 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 15.-Panzcurn arktellurn: a, upper anthecium, lateral view showing thin lemma and 

palea (X 1 j0); b, detail of palea in a showing prickle hairs, silica cells, and stomata (X 500); c, 

detail of upper antheciuni, lemma side, showing bicellular microhair, prickle hair, and sinuous 

silica cells (X 1000); d, detail of upper palea showing stoma (X 1500). Photomicrographs a and 

d based on M’idgren 924 (US), b and c on Hatschbach I4888 (US). 
NUMBER 59 39 

cylindrical, glabrous to hirsute; internodes solid 

or with a small lunien, 15-40 ciii long. iyodes 

obscure, compressed, glabrous. Sheaths shorter 

than the internodes solid or with a small lumen, 

10-2.3 ciii long, keeled, rigid, overlapping at the 

base, glabimus or papillose-pilose along the margins. Lzgule iiieriibranous-ciliate, 0.5-0.7 iiim 

long; collar inconspicuous. Blades linear-lanceolate, acuniinate, 4.3-7.3 cm long, 1-1.8 cni \vide, 

narrow and involute torvard the base, becoming 

flattened and Fvider, sometimes tvith the margins 

involute, rigid, pubescent toivard the base on the 

adaxial sui-face, otherivise glabrous, the margins 

scabrous, the midnerve prominent. Panicles lax, 

diffuse to contracted, pyramidal to oblong, 

iiianv-floIvered, 20-40 cm long, 7-20 cni wide, 

the branches diverging from the axis with the 

spikelets congested along secondary racemes; 

axis cylindrical, scabrous, the branches alternate, 

triqueti-ous, markedly scabrous, densely to 

sparsely hirsute, the axils glabrous to pubescent; 

pedicels short, scabrous or occasionally hirsute. 

Spikelets fusoid, 3.8-5.7 nirii long, 0.7-1 mm 

\$,ide (3.1-3.9 iiiiii long without the awns), 

bror$m, soiiie\vhat compressed laterally, glumes 

and lotvei. leni ma hei-baceo us, weak, prom in en tl y 

scabrous on the nerves. Lower glume ovate-lanceolate, 2.3-3.6 iniii long M’ith an a1t.n 0.9-1.8 

iitiii long, about as long as the lower lemma, 1- 

3-nerved, the inidnerve and awn as well as the 

iiia rgi ii s marked I y scabrous, the inner surface 

scabrous toi\.ard the apex. Upper glume 3.7-5.7 

iiiiii long, niai-kedly scabrous at the apex on the 

i ii 11 e i- s u r face , .3 -11 e r ved , the 11 er ves scabrous , the 

midnerve extending into an awn 0.7-2 mm long, 

this tlvisted or not. LozLler lemma oblong, acute, 

2.8-3.6 iiiiii long, aIvnless, 3-5-nerved, the midnerve scabrous. Lower palea conspicuous, lanceolate, 2.3-3.1 inn1 long, 0.j-0.7 mm \$.ide, hyaline, glabrous, ivith scabrous, denticulate niargins: niale floiver present Lvith 3 stamens. Upper 

anthecium fusiform, 2.3-3.1 iiiiii long, 0.3-0.8 

iiiiii \vide, inembranous, smooth, pale to brown, 

M.ith prominent Iiooks toryard the apex of the 

lemnia and palea and on the margins of the 

lemma, also \vith silica cells, bicellular microhairs 

and stomata ;it the apex of both lemrna and palea; 

lemma .i-nerved: lodicules 2, flat, covering the 

base of the gyneciuiii: stamens 3, stigmas 2 with 

the styles united at the base. Caryopsis dark 

browm ivith aii oblong hiluni; embryo Ih the 

length of the caryopsis 

Kote: In some specimens the rachilla is prolonged in the form of a small point above the 

upper antheciuiii. 

COMMON ~AILlE.-”CaIlar~ll~.” 

SPECIFIC EPITHET.-This species was described by Doell under the name of Panicum 

Aristella instead of aristellum, rvhich would be the 

correct neuter agreement. Comnienting on this, 

Smith and Lt‘assliausen (1 978) felt that the epithet Aristella should be retained and argued that 

the specific epithet had been taken from a genus 

named Aristella 21s it appeared in this form in the 

index to the Flora Brasiliensis of hfar-tius 

(1 877:347-348). However, that index contains a 

number of specific epithets that are capitalized, 

none of \vhich corresponds to the iiaiiie of a 

genus; Arnacites, ,.iturense, and Longispicula are 

examples. The index is therefore not helpful and 

\ve feel there is no strong argument to retain 

Aristella. 

DIsTRIRu.I.ION.-SoutheTn Brazil, from the 

state of Rio de Janeiro to Rio Grande do Sul. A 

hygroplivtic species inhabiting marshes or seasonally inuiid;ited lot%.lands at elevations up to 

1000 111. According to Smith and U‘asshausen 

(1 982) it is a coiiiiiioii species in fields of the 

central planalto of Santa Catarina, \$.here it is 

associated m*ith Hjpogjnium virgatum and Andropogon lateralis. 

ADDITIONAL SPECIMENS SEEN.-BRL4ZIL. 

PARANA: Foz do Rio Taquaral, Hatschbach ??37 

(US): Guarapuava, Kio das Pedras, Pereira 3 

Hatschbach 8004 (US); Prainha, Hatschbach 

28413 (US); hlallet, Hatschbach 15?71 (US): Rio 

das Cinzas, Barra do Perdizes, Hatschbach 8491 

(US): road to Porto \’itoria, Hatschbach 14888 

(US); Piraquara, -22 km E of Curitiba, Tessmann 

s.n., 1 Jan 1949 (US): Rio das Pedras, Hatschbach 

10615 (us). RIO DE JANEIRO: Lvithout locality, 

Glaziou 20576 (US). RIO GRANDE DO SUL: Tupaceretan, Araujo 338 (US). SANTA CATARINA: 6 

km E of Porto Uniao, Smith 3 Klezn 15279 (US); 
40 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

Born Retiro, Reitz 3 Klein 5500 (US); 10 kni E 

of Pop Preto, Smith 3 Klein 1573'6 (US); Porto 

L'niao, Reitz 3 Klein 13671, 13680 (US); \'allos, 

Reit- 3 Klein 3706, 13571 (US); Faxenda Frei 

Kogerio, Poi-to Uiiiao, Reitz 3 Klein 1?6l? (US); 

llorro do Caiiipo ;\legre, Sao Francisco do Sul, 

Reitt 3 Klein 10062 (US); Campo do Areao, 

Santa Cecilia, Reitz U Klein 14150 (US). SAO 

PAULO: Boraceia, margem do Rio Claro, Kuhlmann 2774 (US). 

Taxonomic Position of Panicum killipii 

This species displays no apparent affinity to 

an!. other species of Panicum, as Hitchcock hiniself pointed out in tlie original description. Ho~vever, its affinities to Paspalurn, to Lvhich lve are 

transferring it, become clear in tlie following 

enunieration of characters: 

1 . The spikelets are arranged on unilateral 

1-aceiiies, ivitli one subsessile and the other shortpedicellate. .~Iltliougli both spikelets are usually 

subsessile and appressed to the rachis in Paspalzim, soiiie meiiibers, such as Paspalurn jlavum 

Presl and P. corcovadense Raddi, have pedicellate 

spikelets like Panicum killipii. 

2. The spikelets are plano-convex and obtuse, 

characters that are particularly noticeable in the 

upper anthecium (the presence of a lower male 

flolver obscures this in certain cases). Indeed, the 

spikelets of Panicum killipii and those of Paspalum 

jlazum show ;I great deal of similarity. 

Paspalurn 

Paspalurn killipii (Hitchcock) Zuloaga 8c 

Soderstrom. new combination 

FIGURE 16 

Panicum killipii Hitchcock, 1930b:383. ["Type in the L. S. 

National Herbarium no. 1357803, collected in thickets, 

Aina, betrveen Huanta and Rio Apurimac, Dept. Ayacucho, Peru, alt. 750 to 1000 meters, May 1929, by E. P. 

Killip and .4. C. Smith (no. 22804)." Holotype, US.] 

Perennials 80- 160 cm tall Fvith thick adventitious roots ;it the base. Culms erect, rarely decumbent and rooting on the loiver nodes, branching, 

cylindrical, glabi.ous; internodes hollow, 12-28 

cni long. Sheaths 12-1 7 ciii long, long-ciliate on 

tlie margins, otherivise glabrous. Ligule membranous, laciiiiate, ivitli long i\.hitisli hairs toivard 

the base of the adaxial surface of the blade, 

brotvn. Blades Ianceolate, acuminate, 20-33 cm 

long. 2-3.8 ciii ivide, flat, tlie upper ones cordate, the loi\,er ones M.itli >I pseudopetiole up to 

3 ciii long, the abaxial surface glabrous, adaxial 

glabrous to sparsely pubescent, the margins scabrous to short-ciliate, the basal ones long-ciliate; 

upper blades small. Panicles lax, diffuse, pyramidal, 15-33 cni long, 10-1 7 ciii Ivide, the 

branclies divergent, alternate, \%.idel? separated; 

axis angular , sca br o LI s , tlie branches flattened , 

scabrous, the axils sliort-pubescent, the spikelets 

in pairs and ari-anged more or less unilaterally 

on the raceiiiose branches, one subsessile, the 

other sliort-pedicellate; pedicels shorter than the 

spikelet, scabrous. Spikelets ovoid, plano-convex, 

2-2.4 niiii long, 0.8-1 iiim ]vide, purplish, glabrous or occasionally with some hairs toivard the 

sunitnit of tlie upper glume and IoLver lemma. 

Loxler glume o\xe, acute, 0.2-1 iiini long, nerveless, short-pubescent. Cpper glume and lower 

lemma subequal, obtuse, herbaceous, .%nerved, 

glabrous or pubescent. Lower palea elliptical, 

1.8-2.2 mni long, O..i-0.8 inn1 \vide, hyaline, 

glabrous, the upper margins short-ciliate; male 

floiver present, Ivith 2 lodicules and 3 stamens, 

the anthers 1.3 iiini long. Cpper anthecium ovoid, 

2-2.3 iiini long, 0.8- 1 tiitii Fvide, plano-convex, 

pale, shining, papillate throughout, scabrous at 

the apex of the lemma. Caryopsis 1.4 tiirii long, 

0.7 iiini i\,ide; hilum punctiform, the embryo 

about half as long as the caryopsis. 

Drs-rRIf$uTronr.-This species is knowm only 

from the Peruvian departtnents of Ayacucho, 

Cuxco, and Huancavelica, at 750 to 1200 meters 

el eva t iot 1. 

CVZCO: tvitliout locality, Bues s.n., Jun 1930 (F, 

US). AYACUCHO: Aina, betJveen Huanta and Rio 

Apurimac, Killip 3 Smith 22803 (US); Ocarrapa, 

betrveen Huanta and Rio Apuriniac, Killip 3 

Smith 22491 (US). HUANCAVELICA: Vuelo-Pata, 

ADDITIONAL SPECIMENS SEEN.-PERU. 
NUMBER 59 

FIGURE 16.--Paspalurn killipii, new combination: a, upper anthecium, lemma side (X 100); b, 

detail of a showing simple papillae (X 500); c, detail of immature upper anthecium, lemma side 

(X 500); d, upper antheciuni, Iemrna side, showing bicellular microhairs (X 500). All photomicrographs based on Touar 4615 (US). 

41 
42 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

arriba de L‘irgen-Pampa, a1 SE de Tintay, Tovar 

4615 (US). 

DrscvssroN.-The species exhibits great variation in the length of the lower glume, from 

spikelets in tvhich it is almost absent to those in 

tvhich it attains about half the length of the 

spikelet. 

The species is endemic to Peru, a distribution 

that fits ivell Ivith Paspalum, in which genus more 

than 2.5 species occur exclusively in the Andean 

region of Colombia, Ecuador, Peru, and Bolivia. 

On the other hand, the only species of Panicum 

that are found here are those of wide distribution. 

One specimen, Bues s. n., differs from the 

others in its smaller panicles with densely hirsute 

axis and branches and densely hispid sheaths and 

foliage. The specimen consists only of the upper, 

densel!. branched, part of a culm. 

Taxonomic Position of Streptostachys 

A. N. Desvaux established Streptostachys in 

1810 i\.ith ;I single species, S. asperfolia, lvhich 

he described ;IS iiionoecious and with spikelets of 

both sexes intermixed. He further described the 

female spikelets as having 18-20 glumes. The 

name \vas based on the Greek streptos (twisted) 

plus stachp (spike), in reference to the tH.isted 

disposition of the racemes. Unfortunately, the 

type material ~vas a sterile monstrosity and neither the description nor generic nanie reflected 

the true nature of the genus. In a footnote to the 

description, Desvaux noted that the disposition 

of the flowers \vas quite unusual and served to 

separate the genus from any other known grass. 

After examining specimens that lvere part fertile and part sterile, Palisot de Beauvois (1812) 

emended the original description of the genus. 

Although he described the sterile racemes in the 

same iiianner 21s had Desvaux, he added a description of the fertile panicle and normal spikelets and illusti-ated both types of inflorescence 

togethei. Ivitli details of the spikelet, lodicules, 

and ovai-!. of ;I iiornial panicle. At the same time 

he changed the iiaiiie of the species to S. hirsuta, 

pointing out that the leaves \vere pubescent 

rather than asperous. In the following year Desvaux (1 8 13) redefined the genus and followed 

the modifications made by Beauvois. Trinius 

(1820) accepted the genus and also used the 

name of S. hirsuta. 

In 182.3 Sprengel transferred the species to 

Panicum and called it P. streptostachys, and Trinius (1 826), Kunth (1 829), Steudel (1 855), and 

Doell (in Martius, 1877) followed his lead. Doell 

addition a 1 1 y 1 i s t ed severa 1 s y n on y ins: P. ba la n ites 

Trinius, P. perfoliatum Nees, P. vaginaejlorum 

Steudel, P. rohri Nees ex Steudel, S. asperfolia 

Desvaux, and S. hirsuta Beauvois, and listed P. 

macrophjllum Raddi as doubtful. Benthani (1 883) 

tvas the first to indicate the position of the species 

in the genus by assigning it to section Grandzjlora 

rvith P. macranthum and P. zizanioides. Hitchcock 

(1 922) accepted the species as valid in Panicum 

but effected the combination P. asperzjolium (Desva ux) Hi tchcoc k. 

It ivas not until 193 1 that the original genus 

was re-established by Pilger. For the first time 

since its inception 12 1 years earlier, Streptostachys 

Ivas described on the basis of several natural 

characters: the oblong shape of the lower glunie, 

lvhich reaches 3/4-4L5 the length of the spikelet, 

abscence of a sterile palea, and linear hilum. 

Pilger further pointed out that the base of the 

spikelet is flat and strongly thickened with recurved margins. In 1940 and 1934 the same 

author ernphasized the generic characters of long 

lo\\.er glume, thickened and flattened base, and 

the prominently thickened margins. 

Butzin (1 97Oa) grouped together a whole series of genera of Paniceae on the basis of leaves 

Ivith tessellate venation, adding that all of these 

possessed a s)ndronie of characters that he considered priniitive: the “bambusoid habit”; diffuse 

panicles; presence of a loiver, usually manynerved glume; elongation of the rachilla between 

the lo\\.er glume and the upper antheciuni; presence of a developed lower floLver; and indurate 

upper anthecium. He cited genera that “prove” 

that the Paniceae kvere derived from ancestors 

~v i t h 111 an y - fl o rv er ed s pi ke 1 e t s , i 11 c 1 u di 11 g among 

these Streptostachy, for bvhich he cited teratological panicles in lvliich the spikelets denionstrate a 
NUMBER 59 43 

multiplication of glumes and absence of fertile 

floivers. Butzin regarded this as an extreme case 

of spikelet dinlorpliism that could be interpreted 

as a link betlveen putative many-flowered ancestors and the genera that presently comprise the 

tribe. 

B u t 7, i ii related St rep tosta c hys p h y logen e tical 1 y 

to Acroceras, enumerating the following shared 

characters: amplexicaul leaves, panicles with spikelets ainnged in pairs in racemose branches, 

and caryopses with a linear hilum. He distinguished .4croceras by its laterally compressed spikelets and presence of a rudimentary lower 

flo\\rer. (Although the spikelets of Streptostachys 

are indeed dorsally compressed, a lower flower 

is frequently present. Along with Oplismenus, 

these t\vo genera are further distinguished by a 

linear hiluiii. Homolepis belongs here as well, 

although Butyin included it with genera having 

a punc ti form hi lu 111 .) 

In another paper Butzin (1970b) published a 

systematic treatment of the Paniceae and divided 

it into 11 subtribes, giving to the group already 

mentioned the rank of subtribe, which he called 

hlicrocalaniinae, characterized by leaves with tessellate venation. Curiously, he placed Panicum in 

another subtribe even though many of its species 

share the character assigned to his Microcalami111 spite of iiionstrous material and his niisinterpretations of it, Desvaux's recognition of a 

new genus, Streptostachys, has been validated by 

the years. To the type-species bve are adding a 

iier$r one and transferring yet another from Panicum. The observations that follow refer to the 

genus of three species as tve now recognize it. 

This is manifest with the internodes 

prominent Iietrz.een the loi\.er glume and upper 

antlieciuni. At the same time it is thickened and 

gives the spikelet a particular aspect at its base. 

As ;I consequelice of this peculiar type of rachilla, 

tlie gliriiies arid lo~.er and upper anthecia are 

sti-oiigl!, adnate to it and do not break apart 

easil),, for \i7hicIi reason the spikelet falls at niatirrit), \vitli all of its parts together. In S. asperifolia the rachilla is recurved at the base and 

covei's tlie upper part of the pedicel, but in S. 

nae. 

Kachilla: 

macrantha and S. ramosa it is erect and prominently thickened. 

The hilum is linear and as long as 

the caryopsis. Streptostachys shares this particular 

character Lvith fe\v genera of Paniceae, including 

Acroceras, Echinochloa, Homolepis, Mesosetum, 

Oplismenus, and Tatianyx. 

Round papillae are evenly 

distributed over the lemnia and palea. The anthecium is generally densely pubescent at the 

apex and sparsely so or glabrous toward the base, 

varying in the three species. The hairs are unicellular, long and wavy in S. macrantha and S. 

ramosa, Lvhereas in S. asperfolia they are bicellular and shorter with the distal cell elongated. 

In different specimens variation in the consistency of the lower lemma may 

occur; in sonie spikelets it is niembranous, 

lvhereas in others the median portion is hard and 

the edges menibranous. There are also spikelets 

Lvith the louver lemma indurate throughout and 

Lvith an ornamentation similar to that of the 

upper antheciuni, i.e., with abundant hairs and 

evenly distributed papillae. 

This may be ciliate-formed by a line 

of whitish hairs-to absent, with all variations 

between these extremes occurring within a single 

specimen. 

We do not consider the tkvo follorving characters, M.hich r\'ei'e enumerated by Pilger, to be of 

taxonomic value: 

Lower Glume: Pilger pointed out that the 

lorver glume is generally about :Y4 to 4/5 the length 

of the spikelet and utilized the character to separate Streptostachys from the remaining genera of 

Paniceae. It'hen S. macrantha and S. ramosa are 

included in the genus, the length of the lower 

glume varies from ]/:3 to 4/5 the length of the 

spikelet. In Panirum itself the length of the loiver 

glume varies considerably; for exaiiiple, in the 

groups Parviglumia and Dichotoniiflor-a, it 

reaches to 'h the length of tlie spikelet, to 

Y4 in Panicum, Rudgeana, Sarmentosa, Laxa, 

Penicillata, and approxiniately V4 in Dura and 

Parvifolia. In species such as P. obtusum and P. 

longipedicellatum, the lower glunie is about as 

long as the upper glunie and lower lemnia. '41- 

Caryopsis: 

Upper Anthecium: 

Lower Lemma: 

Ligule: 
44 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 1 'i.--Acroceras zzzanioides: a, upper antheciurn, lateral view, showing thin and crested 

suniniit~ of leninia and palea (X 100): b, upper anthecium, lemma side, showing the crested 

summit (X 100): c, detail of apes of upper lemma, showing prickle hairs and rounded silica 

cells (X .i00); d, same as c but at higher magnification (X 1000). All photomicrographs based 

011 Gillett I6486 (US). 
NULIHER 59 4 5 

FIC~L-RI.: 1 ti.-,$croceras paucispicatum: a, upper anthecium, lemma side, showing the crested 

sutiitiiit and rugose surface (X 50); b, upper anthecium, palea side, showing crested sunimit and 

rugose turbce (X 50); c, detail of summit of lemma shoi\,ing bicellular microhairs. rounded 

papillae, and prickle hairs (X 500); d, detail of apex of upper anthecium, palea side, showing 

S~IIIC structure as in c (X 200). All photomicrographs based on Hassler 12914 (US). 
46 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

though this character generally remains constant 

ivithin each group, it is not considered to be of 

generic value. 

Lower Palea: Contrary to published accounts, 

a lower palea is developed in sonie specimens of 

S. asperqolia. Although rudimentary or reduced 

in sonie cases, it reaches half the length of the 

loiirer lemma in others. In S. macrantha and S. 

ramosa the lolver palea is conspicuous, attaining 

the same size ;is its lemma and sometimes enclosing ;I male flower. In Panicum the lower palea is 

absent in the groups Parviglumia and Cordovensia and in some species of the groups Panicuni, 

Lam, and Penicillata. 

Streptostachys Desvaux, 18 10, emended 

Zuloaga & Soderstrom 

Streptostachys Desvaux, 18 10: 190. 

Plants perennial, cespitose or with short rhi7oiiies. Culms decumbent or ascending, simple or 

branched: internodes hollow. Ligule ciliate, 

formed by a line of whitish hairs, or lacking. 

Blades ovate-lanceolate, flat, subcordate to cordate, amplexicaul. Panicles lax, diffuse to contracted, the spikelets short-pedicellate, aggregated in racemes diverging from the rachis. 

Spikelets oblong, compressed dorsiventrally, disar tic u la t in g be low the g1 u mes, cad uco us, blunt , 

glabrous to shortly hirsute; rachilla thickened 

between the lower glunie and upper anthecium 

and with conspicuous internodes. Glunies 2, herbaceous, pale to purplish, unequal (the lower 

glume rarely equalling the upper). Lower glume 

oblong to ovate, Ih to 4/5 as long as the spikelet, 

1 -7-nerved. Upper glume 5-7-nerved, obtuse to 

acute, frequently not covering the upper anthecium. Lower lemma 3-3-nerved, acute. Lower palea conspicuous, lanceolate, equal in size to the 

lemma or reduced to absent; male floFver sometimes present. Upper anthecium fusoid to narroivly-ellipsoid, pale, shining, indurate, papillosepilose over the entire surface (more so toward 

the summit), and ~vith round papillae distributed 

evenly, margins of the upper lemma enclosing 

the palea; lodicules 2, conduplicate; stamens 3, 

styles 2, stigmas plumose. Caryopsis fusoid, pale 

to light bro\vti: hilum linear: embryo less than 

half the length of the caryopsis. 

A hew W'orld genus, occurring in Trinidad 

and South Anierica and favoring open places, 

savaiiiias, or cerrados r\itIi sandy soils; less frequent in margins of forests or woods. 

TYPE-SPECrEs.-Streptostachjs asperi$olia Desvaus. 

Key to the Species of Streptostachys 

1. Spikelets 3.9-5.1 iiim long; lower glume obtuse, 3/4-4-% as long as the spikelet; rachilla forming a 

thick, recurved disc around the pedicel; lower palea small, ovate, '13 as long as the lemma or 

absent; iipper antheciuni with bicellular hairs toward the apex, the basal cell short, the distal cell 

elongated; papillae encircled by a raised process; axillary panicles present, usually reaching the 

length of the terminal panicle; leaves amplexicaul, 2-4.3 cni wide ............ S. asperifolia 

Spikelets .5.9-9.3 iiim long; lower glume acute, ]/3-'/2 as long as the spikelet: rachilla thickened, 

not recurved at the base; lower palea conspicuous, lanceolate, equal in size to the lemma; upper 

aiitheciiim Lvitli long unicellular hairs throughout; papillae not encircled by a raised process; 

axillary panicles absent: leaves subcordate, not amplexicaul, 0.7-1.3 cm wide ............ .2 

2. Panicles 5-10 cm long, 2-4 cm wide; axils of the racemes glabrous or occasionally sparsely 

1. 

pubescent; plants 50-70 cni tall; blades 7-12 cm long, 0.7-1.3 cm wide ............... 

............................................. S. macrantha, new combination 

.................................................... S. ramosa, new species 

2. Panicles 30-45 cm long, 15-30 cm wide; axils of the racemes densely pubescent with long 

whitish hairs; plants 1.5-2 m tall; blades 35-55 cm long, 1-1.2 cm wide. .............. 
NUMBER 59 47 

Streptostachys asperifolia Desvaux 

FIGURE 19 

Streptostachy asperifolia Desvaux, 18 10: 190. [Type: “Habitat 

in America calidiore.” Holotype, P, not seen; fragment of 

the type, US.] 

Streptostachy hirsuta Beauvois, 18 1250, pl. 10: fig. 1 1. 

[Type: The same as that of Streptostachys asperifoh Desva u x . ] 

Panicum streptostachys Sprengel, 1825:3 16. 

Panicum perfoliatum Nees, 1829: 142. [Type: “Habitat in 

sylvaticis umbrosis ad flumen Amazonum ejusque confluentes provinciae Paraensis et Fluminis Nigri passum.” 

Holotype, M, iiot seen.] 

Panicum balanites J.B. Trinius, 1836:297. [Type: “Colarea 

ad ost. fl. Ama7 (America calidiores, Poeppig).” Holotype, 

LE, not seen: isotype, US sheet no. 1126919.1 

Panicum vaginaeflorum Steudel, 1835:80. [Type: “Guiana.” 

Holotype, P, not seen: fragment of the type, US.] 

Panicum streptostachys f. paleacea Doell in Martius, 1877:23 1. 

[No type cited.] 

Panicum asperifolium (Deskaux) Hitchcock, 1922:489. 

Perennials, 30- 100 cm tall, shortly rhizoniatous. Culms geniculate, decumbent and sometimes rooting at the lou.er nodes, then becoming 

erect, simple or branching, cylindrical to compressed, sparsely hirsute to glabrous, manynoded; internodes Iiollo~, 4-20 cni long, pale to 

purplish. ‘Yodes purplish, compressed, glabrous 

to pubescent. Sheaths 5-10 cni long, densely hirsute to glabrous, Lvitli long tuberculate hairs toMard the mai.gins. Ligule in an arc, shortly ciliate 

or lacking [\.it11 long Lvhitish hairs toward the 

base of the blade; collar hirsute to glabrous. 

Blades ovate-lanceolate, acuniinate, 14-28 cni 

long, 2-4.3 cin rvide. flat, cordate, amplexicaul, 

coninionly tessellate, densely hirsute on both surfaces to glabrous, the niargins ciliate with long 

tuberculate hairs, the midnerve prominent on 

the abaxial surface. Panicles lax, oblong to pyraniidal. 6- 16 ciii long, 1-9 cm wide, the branches 

often diverging from the axis, spikelets shortpedicellate and aggregated in pairs on the 

branches: axis angular, scabrous to hirsute, the 

ti ra n c 11 es ;I 1 t ei-i i at i n g , flat ten ed , g la bro u s to 

sparsely pubescent, the axils pubescent; pedicels 

scabrous. angular, sometimes bearing whitish 

hairs; axillary panicles numerous, similar to the 

terniinal one and borne on long peduncles, these 

15-35 cni long. Spikelets fusoid, 3.9-5.1 mni 

long, 1.5-1.9 niiii wide, glabrous to hirsute with 

a truncate and prominently thickened base. 

Lower glume oblong, obtuse, 3.2-4.7 nim long, 

%-4/5 as long as the spikelet, 5-7-nerved, the 

nerves anastomosing toward the apex. Upper 

glume 3.5-4.7 mm long, 3-7-nerved, the nerves 

anastomosing tolvard the obtuse apex. Lower 

lemma acute, 3.4-4.6 nini long, 3-nerved, glabrous to sparsely pubescent at the base and central zone, hirsute at the apex, membranous to 

indurate (in ivhich case the midnerve and adjacent nerves not manifest), its margins enclosing 

the upper anthecium. Lower palea lanceolate, 

1.3-1.9 iiiiii long, 0.4-0.9 mm wide, brown or 

whitish, hyaline, glabrous, frequently absent; 

male floIver absent. Upper anthecium oblong to 

narroivly ellipsoid, acute, 3.1-4.1 mm long, 1.3- 

1.6 mm tvide, pale, shining, finely papillose 

throughout with the pa pi 1 lae distributed evenly , 

pubescent toward the apex; lodicules 2, conduplicate. Carq’opsis oblong, 2.4-2.8 nini long, 1.2- 

1.3 mm wide, pale or broLvn; hiluni linear; enibryo less than half the length of the caryopsis. 

DIsTRIBrrTIoN.-Inhabitiiig forests in shaded 

spots or more frequently in savannas or cerrados, 

in sandy soils and among shrubs, from Trinidad 

to l’enezuela, the Guianas, and northern Brazil. 

ADDITIONAL SPECIMENS SEEN.-BRAZIL. 

Without locality, Burchell 9291 (US), Gardner 

6108 (US); Gratijeiro, Luetzelburg 25974 (F, US). 

AMAPA: Matapi, Pires & Silva 4799 (US); Porto 

Platon, ,Matto.c 10120 (US); hlapati, kni 116, Black 

c” Lobato 50-9676 (US); 2 kni from Rio Araguari, 

along road from Porto Platon to hlacapa, Pires 

et al. 51084 (US); road to Amapa, kin 108, beginning of Rio Pedreira, Pires 3 Cavalcante 

521 79 (F, NY); Calcoene, frequent at roadside, 

road to gold mines, Pires & Cavalcante 52520 

(NY). BAHIA:w Lvithout locality, Zehntner 3758 

(US); Cruz das Alnias, Pinto 139 (US); Serra do 

Apora, hluritiba, Pinto 256 (US); road MaracasContendas do Sincora (BA 026), kin 2, Mattos 

Silva et al. 213 (NY); Road BR 330, trecho Jequie-Ipiau, 4 kin de Jequie, ,Uori c“ King 12200 

(KY): on road to Abaira, -8 km N of the town 

of Rio de Contas, Harlej et al. 15235 (NY); 31 
48 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGCRF 1 F).--Streptostachys asperfolia: a, upper anthecium, lemma side (X 100); b, detail of a 

showing ~nacrohairs, bicellular microhairs, and rounded papillae (X 200); c, detail of upper 

palea showing bicellular microhairs and simple papillae (X 200); d, detail of simple, rounded 

papillae of upper palea (X 2000). All photomicrographs based on Swallen 4898 (US). 
NUMBER 59 49 

km S of Olindina, along highway BR-116, Davidse et al. 11750 (NY); 16 km NW of Lagoinha, 

on side road to Minas do Mimoso, Harley et al. 

16642 (NY). CEARA: Serrade Baturite, Eugenio 

287 (US); Campo Salles to Crato, Swallen 4?17 

(US); Campo Grande, Swallen 4517 (US); Camocim to Granja, Swallen 46?1 (US); Baturite to 

Guaramirango, Swallen 4431 (US). GOIAS: 2 km

N of Araguaina, Irwin et al. 211?? (F, NY, US). 

MARANHAO: Sao S5o Luis to Sao Jose, Swallen ?46? 

(US); Caxias to Barra do Corda, Swallen ?485 

(US); 39 km NE of city of Grajau, on old road to 

Barra do Corda, Eiten €3 Eiten 10266 (US); Carolina to Sao Antonio de Balsas, Swallen 4144 

(US); about 25 km S of Loreto, between the Rios 

Balsas and Parnaiba, Eiten €3 Eiten 414? (US); 

Ilha de Balsas, region between the Balsas and 

Parnaiba rivers, Santa Barbara, 55 km SSE of 

Loreto, Eiten €3 Eiten 10704 (US). PARA: without

locality, Spruce 95 (US); Marapanim, estrada para 

Jgarape Grande, Silva 496 (US); Marajo Island: 

Caracara river, in plantations, Goeldi 99 (F, US), 

near Soure, Goeldi 299 (F, US); Ilha de Mosqueiro, near Para, Killip & Smith ?0482 (US); 

Ilha de Marajo, Salvaterra, Kauffmann 4 (F, US); 

Soure, Black 50-9071 (US), Swallen 4975 (US); 

Fazenda Camburupy, near Soure, Swallen 4956 

(US); Rio Moju, Fabrica, Black 54-16242 (US); 

estrada Joao Coelho-Vigia, km 40, Black et al. 52- 

14200 (US); Santarkm, Kuhlmann 1740 (US), 

Swallen 3267, ?29? (US); near Santarkm, Spruce 

15, 606, 697 (US); Boim, Tapajos, Kuhlmann 

1922 (US); Mosqueira, Swallen 4898 (US); Breu 

Branco, kni 40 S of Represa Tucurui along highway BR 422, Plowman et al. 9659 (NY); 36 km 

SE of Vigia, along highway PA-140 to Belem, 

Davidse et al. 17597 (NY); Campo de Matapiquara, -1 km E of Matapiquara, 73 km NNE of 

Castanhal by road, Davidse et al. 17896 (NY); 

-73 airline km NE of Castanhal; savanna adjoining the village of Martins Pinheiro, Davidse et al. 

17960 (NY). PARAIBA: Areia, Coelho de Moraes 

854, I156 (US). PERNAMBUCO: Dois Irmaos, vicinity of Recife, Chase 7728 (F, US); Olinda, 

Pickel 2273 (US); Joao Pessoa, Pickel 3852 (US). 

PIAU~: without locality, Lutzelburg 5544, 5547 

(US), Ule 7425 (US), Gardner 2?41 (US); Oeiras, 

Martius s.n. (US); 32.8 km along road S of i\marante, 25 km S of Piaui river, Eiten 3 Eiten 10371 

(US). RIO GRANDE DO KORTE: Pedro Velho, 

Emygdio 1655 (US); Natal, Swallen 4675 (US); 

Nova Cruz to Montanhas, Swallen 481 I (US). 

FRENCH GUIANA. Without locality, Sagob 

1395 (US), Leprieur s.n. (US). CAYENNE: St. Madeleine road, vicinity of Cayenne, Broadway 745 

G U Y A N A. Without 1 oca 1 it y , Sc ho m b u rgk 7 7 4 

(F, US). Waranawa Ranch, Harrison 1047 (US). 

SURINAM. Kayser airstrip, 25 km above confluence with Lucie River, Maguire et al. 5?95? 

(US); Zuid River, Kayser airstrip, Irwin et al. 

5599 I (F); Kaysergebergte airstrip, Freund R-34- 

B (US). 

TRINIDAD. Chaguasamas, Broadway s.n., 12 

Jul 1927 (US). 

VENEZUELA. BOLIVAR: between Los Castil10s de Guayana and Piacoa, Steyermark 86270 

(US); Morichal, Santa Isabel, Cardona 655 (US). 

MONAGAS: 17 km NNW of San Felix and Rio 

Orinoco along hwy 10, Davidse 4604 (NY). 

Drscuss1oN.-The pubescence in this species 

is quite variable, both on the vegetative parts and 

in the inflorescence, with hirsute to totally glabrous specimens encountered. The panicle of 

Swallen 44?1, for example, contains both hirsute 

and glabrous spikelets. 

The lower lemma is frequently indurate with 

a consistency similar to that of the upper; in such 

examples the midnerve and adjacent nerves are 

not manifest. In other cases the lower lemma is 

membranous and similar to the glumes. Even 

though the lower palea is generally lacking or 

poorly developed, it occasionally reaches half the 

length of its lemma, as in Pires 4799. Axillary 

panicles are frequent and numerous in this species and reach the same length as the terminal 

one. 

The upper anthecium is sparsely pubescent 

toward the apex with bicellular hairs on the 

lemma and palea. Sparse long unicellular hairs 

and numerous hooks also occur on the the apex 

of the lemma, as revealed by SEM. Except toward 

the margins of the lemma the entire surface of 

the anthecium is evenly covered with rounded 

(US). 
50 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

papillae, each of these centered on a swelling of 

the anthecium. 

A ligule is generally absent. When it does occur 

it consists of a line of short hairs. 

Bi-okvn (1 977) reported the species to be Cs, 

or non-Kran7, rvith a "C/"C index of -27.0. 

Streptostachy macrantha (Trinius) 

Zuloaga & Soderstrom, new combination 

FIGURE 20 

Panicum macranthum Trinius, 1826:209. [Type: "V. spp. 

Brdsii. (Langsd.)." Holotype, LE, not seen; fragment of 

the type, US sheet no. 974708.1 

Panicum imginatum var. alpha et beta Nees, 1829: 156. [T\pe: 

"Habitat in Brasilia meridionali (Sellow). \'idi in Herb. 

Reg. Berol." Holotype, B, not seen; fi-agnient of the type, 

us s.n.1 

Short-rhizomatous perennials, 30-70 cm tall, 

covered at the base bj. densely villous cataphylls. 

Culms compressed, simple, glabrous; internodes 

hollou., 5- 1 .5 ciii long. 'Yodes pilose to glabrous, 

co 111 13 ressed , dark ; basa I 1 eaves pen is te n t , c u r 1- 

ing. Sheaths 6- 14 ciii long, pale to purplish, glabrous to short-pubescent, the basal ones short, 

overlapping, the upper elongated. Ligule ciliate, 

0..5-1 iinni long, lacking in the lower leaves; collar 

pale to purplish, sliort-pubescent to glabrous. 

Blades ovate-laiiceolate, acunlinate, 7- 14 cm 

long, 0.7-1 .3 ciin M.ide, flat, occasionally rvith 

involute margins, cordate and sometimes amplexicaul, densely hirsute to glabrous, the margins ciliate, the midnerve not differentiated; upper blades coninnoiily small or absent. Panicles 

lax, open, .5-10 ciii long, 1 .3-4 cm wide, longexserted, peduncles 16-33 cni long, the spikelets 

more or less spread along the branches; axis 

angular, glabrous, the loiver branches verticillate, opposite or alternate above, flexuous, glabrous, smooth, uithout spikelets at the base, diverging fi-on) the axis, axils of the Iorver branches 

glabrous to sparsely pubescent; pedicels scaberulous, claviforin. Spikelets fusiform, 5.9-6.8 mm 

long, 2.1-2.5 miin wide, glabrous to hispid on 

the apes of the upper glume and lo\ver lemma, 

greenish to purplish, the rachilla thickened betlveen the loiver glume and upper anthecium and 

with manifest internodes. Louwr glume ovate, 

acute, 2.3-3.5 iiiiii long, lh-lh the length of the 

spikelet, 1 -3-nerved, the midnerve scabrous or 

not to\\xrd the apex. Gpper glume 5-3.8 mm 

long, not completely enclosing the upper anthecium, sparsel!. hispid to glabrous at the obtuse 

apex, .5-7-nerved, the nerves anastomosed to- 

\Yard the apex. LozLler lemma 5.4-6 inn1 long, 

acute, 3-.5-nerved, the nerves anastomosed toMard the apex, densely hispid to glabrous, membranous to indurate. Lower palea lanceolate, conspicuous, 4.3-3.1 nniii long, 1 - 1.4 mni r+.ide, 

hvaline, glabrous; nnale florver sometimes present, Ivitli 2 lodicules, and 3 stamens. Upper anthecium ovoid, 5.1 -.5.9 mi11 long, 1.8-2.1 mm !vide, 

pale, shiiiing, pubescent, covered lvith long, thin 

u 11 ice 11 u 1 a I- I i 1 xi-oha irs , g la bresce 11 t to ward the 

base, finely papillose throughout, the papillae 

rounded and distributed evenly; lemma 5- 

nerved. Carppsis fiisiforni, 3.6 iiiiii long, 1.7 mm 

uide; hiluni linear; embryo less than half the 

length of the cai-yopsis. 

DIsTRIRvTroN.-~ccurriiig in the Brazilian 

ceri-ados of Goak and \lato Gr-osso betiveen 400 

and 1200 111 elewtion and reported from the 

Amaiiiba). range of Paragua),. 

AIIDITIONAL SPECIMENS SEEN.-BRAZIL. 

iVithout state: Rio de Saii Francisco, Pohl 329 

(US); Lagoa Santa, Warming s. n. (IVY). DISTRITO 

FEDERAL: 20 km S of Brasilia on road to Goiania, 

near Rio Melchior, Irwin et al. 8658 (US); Rodovia DF6-Brasilia, Allem U Vieira 1087 (MO). 

GOIAS: without locality, Gwithout locality, Glaziou 22526 (US); 33 

kni S of Caiaponia on road to Jatai, Irwin 8 

Soderstrom 7131 (MO, US); Serra do Caiapo, 30 

kni h of Jatai on road to Caiaponia, Irwin 8 

Soderstrom 7307 (US); -20 km S of Brasilia on 

road to Goiania, near Rio Melchior, Irwin et al. 

8658 (NY). MINAS GERAIS: Serra do Cip6, 110 

km NE of Belo Horizonte, Chase 9297 (US); 

Moi-ro do Cruzeiro, Lagoa Santa, 42 km N of 

Belo Horizonte, Chase YO18 (NY, US); 38 km de 

Paraopeba, Ferreira 1463 (MO). 

PARAGUAY. Sierra de Amambay, Estrella, 

Hassler 101 15 (BAA), Rojas 6298 (BAA). 

DISCCSSION.--AS in S. asperifolia this species is 
NUMBER 59 

FIGURE ZO.--Streptostachys macrantha, new combination: a, upper anthecium, lemma side (X 

100); b, detail ofa showing macrohairs and simple rounded papillae (X ZOO); c, upper antheciutn, 

palea side (X 100); d, upper anthecium, palea side (X 50). All photomicrographs based on 

Glazzou 22526 (US). 
52 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

variable in the consistency of the lower lemma, 

which may be membranous to indurate throughout. In Irwin et al. 8658, for example, there are 

spikelets with the lower lemma totally membranous and similar in aspect to both glumes; in 

others the central part of the lower lemma is 

indurate, smooth, shining, pale, and densely pubescent toward the apex, bearing rounded papillae as well and not distinguishable from the 

upper anthecium. In this latter case the midnerve 

and lateral nerves are not manifest. The lower 

lemma remains membranous and purplish toward the margins and here the nerves are visible. 

Both Kunth (1829) and Doell (in Martius, 

1877) made note of the thickened base of the 

spikelet and also mentioned that the base of the 

panicle was either pubescent or glabrous. The 

illustration in the former work agrees exactly 

with what we here consider to be the species. 

The lower sheaths are persistent and completely envelop the culm, giving protection to 

the plants that are affected by periodic fires. 

Streptostachys ramosa Zuloaga 8c Soderstrom, 

new species 

FIGURES 2 1, 22 

Type Specimen.-BRAZIL, BAHIA: 22 22 km S 

of the Rio Galheirao along highway BR-020, 8 

Apr 1976, 860 m, G. Davidse, T.P. Ramamoorthy 

€+ D.M. Vital 12216 (Holotype, MO; isotype, 

NY). 

Gramina perennia rhizomatibus brevibus, 1.5- 

2 m alta. Culmi erecti, simplices. Foliorum vaginae carinatae, manifeste distichae. Ligula ciliata. Laminae lineari-lanceolatae, 35-62 cm longae. Paniculae laxae, diffusae, 30-45 cm longae, 

axillis raniorum dense pubescentibus. Spiculae 

oblongoideae, 6.3-9.3 mm longae, 2.1-2.5 mm 

latae, glabrae. Gluma inferna acuta, longitudine 

'/3-'/2 spiculae aequans, 3-nervata. Gluma supera 

obtusa vel acuta, 5-nervata. Lemma infernum 

subacutum, 3-5-nervatum. Palea inferna lanceolata, 5.3-7.9 mm longa. Anthoecium superum 

oblongum ad anguste ellipsoideum, 5.4-7.9 mm 

longum, pubescens, omnino subtiliter papillosum. Caryopsis ellipsoidea, hilo lineari. 

Short-rhizomatous perennials, 1.5-2 m tall 

with densely villous cataphylls. Culms erect, fewnoded, simple, cylindrical, glabrous; internodes 

hollow, 8-20 cm long, Nodes purplish, glabrous 

to short-pubescent. Sheaths 15-40 cm long, 

longer than the internodes, overlapping at the 

base and villous, prominently distichous, keeled, 

sericeous to glabrous above, the margins shortciliate. Ligule ciliate, formed by a line of whitish 

hairs 0.8-2.5 mm long or lacking; collar dark 

brown to purplish, glabrous to short-pubescent. 

Blades linear-lanceolate, acuminate, 35-62 cm 

long, 1-1.4 cm wide, flat or with the margins 

involute, rigid, cordate, the margins short- to 

long-ciliate, scabrous, hispid toward the base of 

the adaxial surface, the remainder glabrous or 

densely pubescent on both surfaces with long 

appressed hairs. Panicles lax, diffuse, pyramidal, 

30-45 cm long, 15-30 cm wide, spikelets solitary 

along the branches, subsessile; axis cylindrical, 

undulate, glabrous, the branches verticillate or 

opposite, naked at the base, glabrous, wavy, axils 

densely pubescent, the hairs long, whitish, the 

pulvini dark brown, pedicels short, angular, 

smooth, glabrous, thickened at the apex. Spikelets 

fusoid, 6.3-9.3 mm long, 2.1-2.5 mm wide, glabrous, greenish to brown or purplish, glumes 

and lower lemma with prominent nerves, pubescent or scabrous toward the apex of the inner 

surface. Lower glume acute, 2.2-4.4 mm long, 

%-l/z the length of the spikelet, 3-nerved, shortpilose at the apex. Upper glume obtuse or acute, 

5.3-8.1 mm long, commonly leaving exposed the 

apex of the upper anthecium, 5-nerved. Lower 

lemma subacute, 6.2-8.5 mm long, 3-5-nerved. 

Lower palea conspicuous, lanceolate, 5.3-7.9 mm 

long, 1-2.2 mm wide, hyaline, glabrous; male 

flower sometimes present, with 2 lodicules and 3 

stamens, the anthers 4.3 mm long. Upper anthecium ovoid to narrowly-ellipsoid, 5.4-7.9 mm 

long, pale to brown, 1.9-2.4 mm wide, shining, 

pubescent, with thin whitish hairs, more abundant toward the apex, finely papillose throughout; lodicules 2, the stigmas purplish. Caryopsis 

ellipsoid, 3.8 mm long, 1.9 mm wide, olivaceous; 

hilum linear; embryo a little less than half the 

length of the caryopsis. 
FIGURE ‘LI.--Streptostachys ramosa, new species: a, habit (X 1); b, panicle (X 1); c, spikelet, 

lateral view (x 12); d, scheme of longitudinal section through base of spikelet (X 12); e, 

car)opsis, sho~ing linear hilum (X 12);J lower glume (X 12); g, upper glume (X 12); h, lower 

anthecium (X 12); i, lower lemma (x 12); j, lower palea (X 12); k, stamen (X 12); 1, upper 

anthecium, leninia side (X 12); m, upper anthecium, palea side (X 12); n, upper palea with 

gyneciuni and lodicules (X 12); 0, lodicules of upper anthecium (X 25); p, upper anthecium, 

lateral view (X 12). Didwing a based on Davidse et al. 12216 (MO), b on Hatschbach et al. 36145 

(MO), and C-o 011 both. 
54 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 22.--Streptostachys ramosa, new species: a, detail of upper anthecium, lemma side (X 

ZOO): b, upper anthecium, palea side (X 40); c, base of spikelet showing thickened internodes 

(X 40); d, detail of upper palea showing macrohairs and simple rounded papillae distributed 

evenly over the surface (X 200). Photomicrographs a, b, and d based on Harley 16876 (US), c 

011 Heringer 9590 (NY). 
NCMRER 59 55 

PARATYPES.-BRAZIL. BAI~A: 15 kni S of the 

intersection of highl\’ay BR-020 and the Rio 

Roda \‘elha, G. Davidse et al. 12085 (MO, NY, 

US); Sen-a do Curral Feio, 22 km NW of Lagoinha, on side road to Minas do Minioso, 6 Mar 

1974, R..Zl. Harley et al. 16876 (MO, NY, US); 

BR 242, km 216, 12 k~ii i% of Lencois, S. Mori 

13335 (NY); Espigao Mestre, -100 kni WSW of 

GOIAS: region region of Chapada dos i’eadeiros, 38 km 

N of Sao Joao da Alianfa, at W long. 47”30’, S 

kit. 14”30’, fi;. Y. Dazllson 14554 (US). M.4TO 

<;ROSSO: Chapado dos Guimaraes, G. Hatschbach 

et al. ?5145 (hIO, NY); eiitre Queiniada e Rio 

\‘el.de, \vitliout collector (MO sheet no. 

23 12029). MINAS GERAIS: Tres Marias, 26 Feb 

1964, E.P. Heringer 9590 (NY); -20 kni S of 

Alto do Paraiso (formerly Veadeiros), H.S. Irwin 

et al. 24716 (NY); -33 kni YE of Francisco Sa, 

road to Saliiias, H.S. Irwin et al. 23126 (SY). 

DIsTRIRuTIoN.-Species of the Brazilian cerrados, occurring betlveen 800 and 1 100 111 elevation. 

DrscussroN.--‘I’Iiis species is related to S. macrantha, from i$.hich it is distinguished by the size 

of the plants, leaves, and panicles, the branches 

of the latter. iiiiicli longer and the spikelets borne 

iiiore distaiit froni one another than in S. macrantha. l’he densely pubescent axils of the panicle branches furthei- distinguish it. 

The only basis for assigning Glariou 20123~ 

(US) to this species is a fragiiient of the panicle 

Lvith the follo\ving annotation by A. Chase: 

Specimen in Paris lib. labeled Panicum grandijlorum n. 

sp. agrees with Glaziou 22526 and Chase collections but 

is 70 cm tall, the panicle 25 cm long, the ascendingspreading branches to 9-1 0 cni long. 

l’here is also a fragnient of the same specimen 

from \’ienna. The type-locality must be erroneous ;is given on the label: “Brazil, Rio. Glaziou 

20123a.” Obviously the species does not occur in 

Rio de Jaiieiro and the \,eracity of this labellike so niany of Glaziou-is open to question. 

It is possible that this species was first described 

bv Xlez under the miiie Panicum mirabile Mez 

(1 92 1) not ;I. Braun (1 846) nor M’alpers (1 848- 

B. ‘11 ._ I eiras, It’. R. ‘Anderson et al. 36657 (MO, NY). 

1849). In his publication Mez gave very brief 

descriptions of his new species, making their 

identification difficult. The author’s reference to 

the large size of the plant and striking similarity 

of spikelet characters betiveen P. mirabile and S. 

ramosa suggest that ive may be dealing ~vith the 

same species. A fi.agment of the type, rvhich 

consists of a racemose branch of the panicle, is 

at US and is labeled “Panicum mirabile Mez. Brasil 

occ. Tambei-lik.” The holotype from the Berlin 

Museum consists only of a fragment of the panicle and a leaf and even though the aspect of the 

panicle matches that described for S. ramosa, the 

absence of fuller material does not allow us to 

arrive at a definitive conclusion regarding the 

identity of P. mirabile. The point is not critical, 

ho\vever, because the name of this species is 

invalidated by tiz~o earlier epithets. 

CHROMOSOME NUMRERS.--n = 27 (Davidse 

and Polil, 1978, as Panicum macranthum Trinius). 

Taxonomic Position of Tatianjx 

Among the niost beautiful of paiiicoid grasses 

in tropical Anierica is a species that was named 

Panicum arnacites by Trinius for a grass that 

inhabits the “campo rupestre” of Brazil in the 

states of Bahia, Para, Goais, llinas Gerais, and 

Mato Grosso. The epithet arnacites, Ivhich conies 

from the Greek ivord for “~.oolly,” aptly describes the long-hairy spikelets of this species. 

Our comparison of this Panicum Lvith other 

members of the tribe confirms its unique position. A linear hilum immediately distinguishes it 

from other species in the genus as does the 

position of the pedicel relative to the spikelet. 

The pedicel is falcate at the apex and the spikelet 

held in an oblique position, behind the upper 

glunie and upper lenima Lvher-e it form a pubescent callus. In Panicum the hilum is round and 

basal and the pedicel is truncate at the apex with 

the spikelet held erect. A linear hilum is found 

in other panicoid genera such as Streptostachjs, 

and a callus is found in Chaetium and Digitariopsis. 

Trinius did not refer to the caryopsis when he 

described the species nor \\.as the hilum mentioned in the latter references of Trinius (1 834), 
56 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

Steudel (1 855), or Doell (in Martius, 1877). The 

unusual placement of the pedicel and spikelet 

had apparently also never been considered as an 

important character to separate this species from 

others in Panicum. 

In comparison with other panicoid grasses, 

Panicum arnacites is superficially similar to Anthaenantiopsis and Leptocoryphium, in which the 

spikelets are lanate or pilose. In the latter the 

anthecium is delicate, not rigid, and the margins 

of the upper lemma are hyaline and do not cover 

the apex of the palea. The anthecium is open at 

the summit and the lower glume is diminutive. 

In the former genus the upper anthecium is also 

open at its summit and the spikelets are arranged 

on unilateral racemes rather than in a panicle. 

Because Panicum arnacites cannot be accommodated in any known genus of the Paniceae, 

we are establishing a new genus for it, which we 

are calling Tatianyx, in honor of Sra. Tatiana 

Skvortzov Sendulsky (born 1922, Harbin, Manchuria), of the Instituto de Botanica inSaoo Paulo, 

an authority on the grasses of Brazil. 

Tatianyx Zuloaga & Soderstrom, new genus 

(Poaceae: Panicoideae) 

Gramen perennis. Culmi erecti, simplices. Ligula ciliata. Laminae lineari-lanceolatae. Paniculae 

laxae, pyramidales; pedicelli longi, flexuosi, apice 

falcati, facie dorsali spiculae oblique affixi. Spiculae ellipsoideae, argenteae. Gluma inferna longitudine ‘/~-~/4 spiculae aequans. Gluma supera 

5-7-nervata. Lemma infernum 5-7-nervatum. 

Palea inferna lanceolata, interdum florem masculum continens. Anthoecium superum ellipsoideum, induratum, papillas compositas superficiares gerens. Caryopsis ellipsoidea, hilo lineari. 

TYPE-SPECrEs.-Tatianyx arnacites (Trinius) 

Zuloaga 8c Soderstrom, new combination. 

Tatianyjc arnacites (Trinius) Zuloaga & 

Soderstrom, new combination 

FIGURES 23, 24, 25 

Panicum arnacites Trinius, 1832:117. [Type: “Figura ad 

specimen Brasilianuni.” Holotype, LE, not seen; fragment 

of the type, US sheet no. 974682.1 

Cespitose perennials 40- 100 cm tall with 

densely villous cataphylls. Culms erect, cylindrical 

to compressed, glabrous or sparsely pubescent 

near the nodes, simple; internodes hollow, 4-20 

cm long. Sodes purplish, long to shortly pubescent bvith whitish hairs. Sheaths 5-26 cm long, 

longer than the internodes, the lower ones enveloping the culni, densely to sparsely pubescent, 

the upper ones glabrous. Ligule ciliate, formed 

by an arc of whitish hairs 0.3-0.4 mm long; collar 

glabrous or short-pubescent. Blades linear-lanceolate, acuniinate, 10-36 cm long, 0.2-0.4 cm 

wide with the margins involute, rarely flat, narrowed at the base, ciliate along the lower margins, the adaxial surface sericeous, the abaxial 

pubescent; upper blades small, inconspicuous. 

Panicles lax, diffuse, pyramidal, many-flowered, 

6-1 3 cm long, 4-9 cm wide, exserted, peduncles 

15-24 cm long, almost completely included in 

the upper leaves when young, the spikelets borne 

on long flexuous pedicels, axillary panicles sometimes present; axis cylindrical or angular, 

smooth, glabrous, usually purplish, the branches 

alternate, opposite or verticillate, smooth, thin, 

glabrous, wavy, the axils densely pubescent to 

glabrous; pedicels long, glabrous, smooth, flexuous, falcate at the apex, positioned obliquely on 

the dorsal side of the spikelet. Spikelets ellipsoid, 

4-4.5 mni long, 1.2-1.4 mni wide, silvery-villous 

with long rigid rvhitish hairs, exceeding the apex 

of the glumes and lower lemma in length; glumes 

and lower lemma herbaceous, glumes and anthecia separated by prominent internodes. Lower 

glume acute, 2.3-3 mm long, ‘h to 3/4 as long as 

the spikelet, 3-5-nerved, glabrous on the inner 

surface. Upper glume acute, 2.8-3.5 mm long, 

leaving exposed the apex of the upper anthecium, 5-7-nerved. Lower lemma acute, 3.2-4 mm 

long, glume-like, 3-7-nerved. Lower palea lanceolate, 3.2-4.3 nim long, 0.7-1 mm wide, long to 

short-pilose on the upper margins, otherwise glabrous, hyaline; male flower sometimes present 

with 3 stamens, the anthers -3.3 mm long. Upper 

anthecium ellipsoid, 2.9-3.7 mm long, 1-1.4 mm 

wide, glabrous, indurate, shining, pale, with long 

prickle hairs at the apex of the lemma, this and 

the palea covered by compound papillae distrib- 
FIGUR~: P:J.--Tatianyx arnacites, new combination: a, habit (X 1); b, stamens (X 18); c, lower 

pale~i, inner surface (X 18); d, lower palea, outer surface (X 18); e, caryopsis, embryo side (X 

18); f; IoM.~~ lenima, inner surface (X 18); g, caryopsis, showing linear hilum (X 18); h, lower 

gl~iiiie (X 18); i, upper glunie (X 18); j, lower lemma (X 18); k, upper anthecium, lemma side 

(x 18); I, pail. of spikelets, showing oblique attachment of-pedicels (X 12); m, spikelet, upper 

gluiiie side, showing oblique callus (X 12); n, upper anthecium, lateral view (X 18); o, upper 

antheciuni. plea side (X 18); p, lodicules (X 35); 9, upper palea showing gynecium and lodicules 

(X 18); r, upper lemma (X 18). All drawings based on IrzLlin 2 Soderstrom 6959 (US) except e 

aiid g based on Pires 2947 (US). 
58 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 24.--Tatianjx arnacites, new combination: a, base of spikelet showing oblique callus (X 

200); b, base of spikelet, upper glurne side, showing oblique callus (X 150); c, falcate pedicel, 

lateral view (X 200); d, pedicel, locus of attachment with spikelet (X 200). All photomicrographs 

based on E'iten 6752 (US). 
NUMBER 59 

FIGURE 25.--Tatianyx arnacites, new combination: a, upper anthecium, palea side (X 200); b, 

upper antheciuni, lateral view, showing prickle hairs on apex of lemma and stomata below (X 

200); c, upper anthecium, lemma side (X 500); d, detail of upper palea showing compound 

papillae (X 2000). All photomicrographs based on Eiten 6752 (US). 

59 
60 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

uted evenly over the surface. Caryopsis ellipsoid, 

2.2 nini long, 1.1 nim \vide, brown; hilum linear, 

;IS long ;is the caryopsis, embryo -’h as long as 

the caryopsis. 

~rsTRI~L~~rIoN.-~ndeniic to the “campos rupestres” of Brazil in the states of Para, Goias,

Minas Geixis, and Mato Grosso, in rocky or sandy 

soils at elevations of 800-1 400 m: occasionally 

burned over. 

ADDITIONAL SPECIMENS SEEN.-BRAZIL. 

BAH~A: near 6 km N of the town of Rio de Contas 

on road to Abaira, Harley et al. 15085 (MO, KY, 

US). GOIAS: near 33 km S of Caiaponia on road 

to Jatai, Irwin 3 Soderstrom 6959 (US). MATO 

GROSSO: Fazenda Capa0 da Taquara, Hatschbach 

32469 (RIO); Faxenda Urubu Branco, Pires @ 

Silva 11318 (US); 7 Quedas, Hatschbach 33145 

($10, NY, US). MINAS GERAIS: Estrada Concei- 

$50 do Cerro, Occhioni s/n., Dec 1940 (US): Serra 

do Cipo, perto do Hotel Palacio, Black 3 Magalhies 51-12039 (NY, US); Chapeo de Sol, Serra 

do Cipo, Chase 9191 (US), 9207 (NY, US): Serra 

do Cipo, along the road at km 134-1 33, Eiten 

6752 (US). PARA: Ariramba, Ducke 8015 (US). 

DrscussroN.-Although it is most common in 

Panicum for the spikelet to be even on the pedicel, it is sometinies twisted as in the case of P. 

hirtum, P. cervicatum, and P. rudgei. In these 

species, however, the pedicel is claviform and 

truncate at the apex and there is no callus. 

In the genus Plagiantha Renvoize the pedicel 

is also truncate and the spikelet lacks a callus at 

its base, hvitli the spikelets disposed in oblique 

form in the panicle. The morphology of this 

genus is therefore similar to that of the species 

of Panicum mentioned above. 

Tt4.o specimens from Mato Grosso (Hatschbach 

32469 and 33145) are about 1 111 tall, exceptionally robust, possess broad leaves that are flat 

throughout, and have lax and diffuse panicles. 

W’e consider these to represent extremes in the 

variation of the species, as in smaller specimens 

(Irmin 3 Soderstrom 6959, for example) small and 

involute blades occur along with larger flat ones. 
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