SMITHSONIAN CONTRIBUTIONS TO BOTANY NUMBER 11 

Morphological and Anatomical 

Considerations of the 

Grass Subfamily Bambusoideae 

Based on the 

New Genus Maclurolyra 

Cleofe/ E. Calderon 

and Thomas R. Soderstrom 

SMITHSONIAN INSTITUTION PRESS 

City of Washington 

1973 
ABSTRACT 

Caldeoh, Cleoee E., and Thomas R. Soderstrom. Morphological and Anatomical Considerations of the Grass Subfamily Bambusoideae Based on the New 

Genus Maclurolyra. Smithsonian Contributions to Botany, number 11, 55 pages, 

24 figures, 1973.-hPaclurolyra tecta, a new genus of grasses from Panama, is 

described. Features of its leaf anatomy and epidermis, seedlings, inflorescence 

morphology, floral structure, and cytology, indicate that it is a member of the 

tribe Olyreae of the subfamily Bambusoideae. A description is given of the 

“bambusoid” type of leaf anatomy, as well as comments on the vascular bundle 

sheaths in grasses, and chloroplast structure and photosynthetic pathways as new 

criteria in grass taxonomy. The phylogenetic position of Maclurolyra is discussed 

and a list of genera comprising the Bambusoideae is presented. 

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

in the Institution’s annual report, .“tr~ithsotiinn Year. SI PRFSS XuliBER 4782. SERIES COVER 

DESIGN: Leaf clearing from the katsura tree Cercidiphjllum jafionicutn Siebold and Zuccarini. 

Library of Congress Cataloging in Publication Data 

Calderbn, Cleofe E. 

Morphological and anatomical consideration5 of the grass subfamily Bambusoideae based on 

(Smithsonian contributions to botan), no. 11) 

Bibliography: p. 

1. Maclurolyra. 2. Bamboo. 3. Botanj-Morphology. 4. Botany-Anatomy. 5. Bamboo-Panama. 

I. Soderstrom, Thomas R., joint author. 11. Title. 111. Series: Smithsonian Institution. 

Smithsonian contributions to botany, no. 11 

QKlS2747 no. 11 [QK495.G74] 581’.08s [584’.93] 72-8955 

the new genus Maclurolyra. 

For sale by the Superintendent of Documents, C.S. Goternment Printing Office, Washington, D.C. 20402 

Price 95 cents domestic postpaid or i0 cents GPO Bookstore 
Contents 

Page 

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

Acknowledgments ....... ...................... 5 

Materials and Methods ......................... .... 6 

iMacluiolyia tecta, new genus and species ............................... 6 

Torsion of the Leaf and Inflorescence ....... 

Morphology of the Inflorescence ................ ................... 15 

Floral Features . . ........................... 

Lodicules ... ............................................. 20 

S taminodes ............................................ 21 

............................................ 27 

Starch Grains ..... ............................... Leaf Anatomy , , , , . ......................... 28 

Seedling ...................................................... 12 

Gynoecium , , , . ...................................... 22 

Cytology . . * . . , . , . , 

The Epidermises ...................................... 

Olyroid Type of Siliceous Cell ................................ 36 

The Bambusoid Type of Leaf Anatomy ......................... 

Chloroplast Structure and Photosynthetic Pathways ...................... Phylogenetic Position of Macluiolyra ................. ........ 44 

Appendix 2: List of Material Studied 

The Transverse Section of the Lamina ............ 

. , . 36 

38 

40 

46 

................................. 52 

............................ 52 

The Vascular Bundle Sheath in Grasses ................................ 

Literature Cited ............ ................................ Appendix 1 : Genera of the Subfamily Bambusoideae Aescherson and 

Graebner ...... 

Index to Grass Genera and Species . . ......................... 54 

iii 

Morphological and Anatomical 

Considerations of the 

Grass Subfamily Bambusoideae 

Based on the 

New Genus Maclurolyra 

Cleofe' E. Calderon J 

and Thom as 

Introduction 

Accounts of the great diversity of species that 

are found in tropical rain forests are common, 

but mostly these are based on inventories of the 

trees that are the conspicuous element of this 

biome. Less attention has been paid to the 

herbaceous vegetation of the understory where the 

decrease in illumination, change in light quality, 

and relati1 ely high humidity create conditions 

which are hostile to most plants. The majority of 

herbaceous plants that thrive under such conditions in the rain forests of tropical America belong 

to relatively few families-Araceae, Bromeliaceae, 

Commelinaceae, Alarantaceae, Musaceae, Orchidaceae, Zingiberaceae. Although they do not constitute a significant part of this understory vegetation, 

either in number of species or in individuals, representatives of the grass family also occur here. 

The new genus that we are describing here 

occurs in Panama where it has so far been located 

in forests of two areas-Santa Rita, on the Atlantic 

slope, and Cerro Jefe, on the Pacific slope (Figure 

1). Lumbering trails have afforded botanists the 

Cleofe E. Caldeidn and Thomas R. Soderstrom, Department 

of Botany, Sattonal Museum of Natural History, Smithsonian 

Institution, Washington, D.C. 20560. 

R. Soderstrom 

opportunity to reach areas of virgin forest previously inaccessible in Panama and Maclurolyra is 

only one of many new plants found in recent years 

in such forests. 

Santa Rita is an area of primary forest situated 

on an undulating terrain, which is traversed by 

numerous streams and creeks, and ranges in elevation from about 200 to 450 meters. From April 

through December heal J rains occur almost daily. 

Recent collections made in late October and early 

Noleniber, at the peak of the rainy season, showed 

all plants to be in flower, with some in fruit, and 

with the presence of many seedlings around the 

parent clumps. The type-collection was made in 

earl) hlaich, at the end of the dry season. At 

this time the plants were in flower and many 

old inflorescences were also found. Apparently 

Mnclurolyra is in flower throughout the year with 

the most profuse flowering occurring during the 

rainy season. 

Plants of Moclzirolyra grow in small clumps 

scattered throughout the forest, usually around or 

near trees or under plants of larger size. In some 

places they grow in association with grasses of the 

related genus, Cryptochloa (Figure 2a,c). All of 

these are found in reddish soil and apparently 

thrive only where it is shaded and humid. Plants 

1 
2 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 1.-Map of Panama showing localities where Maclurolyra tecta has been collected: 

[SR=Santa Rita, CJZCerro Jefe, cross-hatched area=Canal Zone]. 

of Maclurolyra left exposed in nearby cut.over 

areas of forest were found to be stunted and with 

few, small, poorly developed inflorescences-presumably in response to the intense illumination 

and decrease in humidity. Maclurolyra was found 

also, but in less abundance, in some areas of Cerro 

Jefe, a forest region on the Pacific slope of Panama. 

The higher elevation (ca. 800 meters), where 

cooler and less humid conditions are encountered 

than at Santa Rita, possibly accounts for the reduction in numbers of plants. 

Studies of the morphology and anatomy of this 

peculiar new genus have revealed that it is related 

to Olyra and grasses of the tribe Olyreae (“olyroid 

grasses”), which tribe we include in the subfamily 

Bambusoideae, as had Roshevitz (1946) and 

Parodi (1961). (For a brief account of the 

morphology and anatomy of members of this tribe 

see Calderon and Soderstrom, 1967.) Recently we 

have discussed the pollination biology of some 

grasses of the Olyreae, with comments on the 

relationships of some of these herbaceous grasses to 

the woody bamboos, all of which we refer to in a 

general way as “bambusoid grasses” (Soderstrom 

and Calderh, 1971). 

Our studies on the new genus have been made 

from the standpoint of its morphology and 

anatomy, with a view not only to elucidating its 

systematic position within the grass family, but 

with the objective of clarifying and defining more 

precisely the “bambusoid type” of leaf anatomy. 

This allows us the opportunity to present some 

general considerations on the morphology, anatomy, 

and taxonomy of the subfamily Bambusoideae, 
NUMBER 11 3 

FIGURE P.--Maclurolyra tecta in the field (Santa Rita forest, Panama): A, Mature plant (indicated by arrow) growing in association with plants of Cryptochloa; B, close-up of adult plant; 

c, close-up of adult plant with a plant of Cryptochloa in the background. 

including remarks on the tribe Olyreae. We have colleague, Floyd A. McClure (1897-1970). We are 

felt it useful to present at the end of this report a indebted to him for the countless hours of conlist of all genera which we consider to be members sultation over the years regarding problems of 

of the subfamily Bambusoideae (Appendix 1). bamboo morphology. He became familiar with the 

The genus is named in honor of our late new genus as we studied it and shared with us, in 
FIGURE 3.-InHorescence of dlnclurolyin tecta in the field (Santa Rita forest, Panama) : A, Newly 

emerging inflorescence as seen from abo1e; n, inflorescence in front of the blade; C, inflorescence 

beginning to twist; D, inHoi.escence at a late1 stage in back of the blade; E, old inflorescence 

bent downward in back of a blade (see arrow), and one still in front of the blade; F, inflorescence axis bent downward (see arrow). 
SUMBER 11 

its interpretation, the wisdom he had acquired 

during a lifetime dexoted to the study of bamboo. 

The specific name derives from the Latin word 

for “cover,” in allusion to the uppermost blade on 

the flowering culm rvhich covers the inflorescence 

in umbrella-like fashion, shielding the flowers from 

the rain (Figure 3). 

\\'bile lumbering trails such as those at Santa 

Rita allow us access to such genera as iWaclurolyra, 

these trails also signal the imminent destruction 

of these same forests. The actual site of the typecollection of Maclzirolpra-primar) forest in 1968- 

was revisited in 1971 and found already cleared-a 

part of the ecosystem that took so long to evolve 

destroyed forever. It is incumbent upon us, as 

biologists, to encourage that parts of these forests 

be protected so that in the future plants of genera 

such as i+fuclziro/yru can still be found in their 

natural habitat rather than in herbaria as mere 

dried records of the past. 

.~CKNO~\’LEDC1MENTS.-we feel our deepest gratitude to our major professors who were responsible 

for our basic training in agrostology, Professor John 

R. Reeder (Laramie, T\”yoming) and the late Profesor Ingenieio Lorenzo R. Parodi (Buenos Aires). 

The present study was possible only because of 

the support and facilities many offered institu- by 

tions and offices, and the personal assistance, 

cooperation, and advice rendered to us by colleagues 

in the United States, Latin America, Europe, India, 

and Ceylon. Primary credit is to be given to the 

Smithsonian Institution, LVashington, D.C., for 

grants from the Smithsonian Research Foundation 

to the junior author which have provided for the 

laboratory studies to be carried out. Support for 

Calder6n to traLel to Central and South America 

during 1967-1968 Tvas provided by the Smithsonian’s 

Office of Systematics and Office of Ecology, and for 

this trip a traiel grant was awarded by the Office 

of Scientific Affairs, Organization of American 

States. The field work in Panama, during which 

period the new genus was collected, was possible 

onl) because of the assistance given by Dr. Robert 

L. Dressler (Smithsonian Tropical Research Institute, Balboa, Canal Zone) to whom we are 

especially indebted. A grant from the Smithsonian’s 

Office of International Activities allowed Calder6n 

to spend some time in Europe on the way to India, 

and provided the opportunity to discuss matters 

relating to the new genus with specialists in various 

institutions. We would like to extend our thank3 

to Dr. C. R. Metcalfe (Jodrell Laboratory, Royal 

Botanic Gardens, Kew, England) for his review 

and criticisms of the anatomical studies of the new 

genus; and at the herbarium of the Royal Botanic 

Gardens, Kew, to the renowned agrostologist, Dr. 

C. E. Hubbard, for his taxonomic suggestions. The 

moi phological discussions concerning grasses, and 

particularly the inflorescence of the new genus, 

were made Tvith specialists at the Universitat Mainz, 

LYest Germany, and particular acknowledgment is 

made to Prof. Dr. H. Weber (Director, Institut fur Institut fur 

Spezielle Botanik) and his colleagues at the same 

Universit), Profs. Drs. D. Hart1 and S. Vogel. We 

ivould like to express our very deep gratitude to 

the eminent morphologist, Prof. Dr. Wilhem Troll, 

also of hlainz, for the numerous hours he devoted 

to Calder6n in his laboratory, discussing the 

inflorescence morphology of Maclurolyra. His 

advice, suggestions, and encouragement to continue 

in the difficult study of grass inflorescence morphology, are all deeply appreciated. TYe are grateful 

as well for the advice given by Dr. H. J. Conert 

(Natur-Museum und Forschungs-Institut Senckenberg, Frankfurt), Dr. H. Jacques-Felix (Museum 

National d’Histoire Naturelle, Laboratoire de 

Phanerogamie, Paris), Dr. F. Bugnon (Faculte des 

Sciences de Dijon, France) , Dr. G. Bocquet (Institut 

fur Spezielle Botanik, Eidg. Technische Hochschulle, 

Zurich), and Dr. E. Mora-Osejo (Instituto de 

Ciencias Katurales, Bogotzi). \Ye would like to 

thank Dr. V. Puri (Meerut University, Meerut, 

India) for his advice on embryological problems in 

the Gramineae and his generosity in allowing the 

use of his laboratory and facilities in India. Dr. 

Pierre Morisset (Universitie Laval, Quebec) was 

kind enough to study the chromosomes of the new 

genus and pro\ ide the photograph which appears 

in Figure 14d. 

IVe are grateful to llrs. Nina Smith (Hunt Botanical Library, Pittsburgh), who assisted in the 

transliterations of the Russian titles and in translating passages from various Russian and German 

papers. 

\Ire appreciate the suggestions and assistance 

provided by several colleagues at our own institution-Dr. E. S. Ayensu, Dr. Jose Cuatrecasas, Dr. 

Mason E. Hale, Jr., the late Mr, Conrad V. Morton, 

Dr. Lyman B. Smith and Dr. William L. Stern. 

TVe were fortunate to have the habit drawings 
6 ShIITHSOA‘IAN CONTRIBUTIONS TO BOTANY 

pi epared by our illustrator, Mrs. Gesina Berendina 

Threlkeld (GBT) of Delta, Alaska, and a few of 

the sketches by Mr. Christopher Reinecke (CR) of 

SVashington, D.C. 

MATERIALS AND MEmoDs.-Plants were collected 

in the field and herbarium specimens prepared in 

the usual fashion by placing them between newspapers in a plant press and drying with supplementary lieat. Living plants were collected in the 

area of Santa Rita in October 1971 and taken to 

Sl’ashington, D.C., where they are under cultivation 

in a greenhouse. 

Field photographs were taken with a Nikon F 

camera (equipped with a Nikon Photomic-TN 

Finder), using the Micro-Nikkor 55mm lens and 

Kodak Tri-X film (ASA 400), without an additional light source. A tripod was used in all 

instances. 

Material for morphological, anatomical, and 

cytological studies was fixed in the field at time of 

collection. For cytological studies young inflorescences were fixed in a mixture of three parts 95 

percent EtOH to one part glacial acetic acid, and 

transferred within 24 hours to 70 percent EtOH 

and stored under refrigeration. Inflorescences, 

leaves, and seedlings were fixed in FAA (5 cc 

formalin: 5 cc glacial acetic acid: 90 cc of 50% 

EtOH) . The blade of the first or second completely 

developed leaf from the uppermost part of the 

culm was selected for preservation. Young inflorescences were also fixed, in a mixture consisting 

of equal parts of glycerine and lactic acid (Bersier 

and Bocquet, 1960), 

Studies of the leaf anatomy were made on 

material preserved in FAA. After washing, the 

sections were cut by hand with a razor blade from 

the middle portion of the blade, and mounted, 

without staining, in glycerine or glycerine-lactic 

acid. 

Preparations of epidermises of the leaves were 

made by the standard technique of scraping and 

mounted, without staining, in glycerine. Some 

preparations were stained with a weak solution of 

safranin, without dehydration, to facilitate the 

observation of the siliceous cells and microhairs. 

The gynoecia were dissected and mounted, without staining, in glycerine-lactic acid and studied 

with phase contrast and dark field illumination. 

The glycerine-lactic acid mixture acts not only as 

a good clearing agent but preservative as well and 

the material needs no further transferring after 

fixing in the field. Flowers treated in this way are 

the most suitable for studies under phase contrast 

and polarized light. Flowers so treated were used 

in the studies of the venation of glumes, lemmas, 

and paleas, and the vascular traces of the gynoecium. 

These parts were mounted in the same clearing 

agent. The ovule structure was also studied from 

material in this preservative. 

Herbarium material, when used in dissection, 

was treated with “Aerosol OT Solution” (Fischer 

Laboratory no. SO-A-292). Spikelets were softened 

by treatment with a few drops of this solution for 

a few minutes and kept moist by drops of water 

during dissection. 

For studies of starch the single mature caryopsis 

available was soaked in a mixture of equal parts 

Aerosol OT Solution and water for one and a half 

hours. Cross-sections were made by hand, cutting 

with a razor blade the material positioned between 

two pieces of pith. The sections were stained with 

a drop of IKI for about 20 seconds, washed in 

water, and mounted in glycerine. 

Anatomical observations were made with the 

Leitz Ortholux microscope, equipped with plano 

objectives, and photomicrographs were taken using 

this microscope and Kodak Panatomic-X film 

(ASA 32). Bright field, phase contrast, polarized 

light, and dark field were used. Dissections were 

studied under the Wild M 5 Stereo-microscope and 

drawings were made with the aid of the Wild drawing tube, Anatomical drawings were made using 

the SVild M 20 microscope, also with the aid of a 

SVild drawing tube, Illustrations of the habit of 

the plant were made from herbarium specimens 

and field photographs. 

Voucher specimens of the plants reported in this 

paper are filed in the United States National 

Herbarium, Smithsonian Institution. The collection of material in liquid preservative is also 

maintained at the same location. 

Maclurolyra tecta, new genus and species 

FIGURES 4-7 

DEscRIpTroN.-Gramen perenne sylvarum umbrosarum, usque ad 48 cm altum. Culmi erecti, 

sine ramis, plerumque 20-48, cm alti, nodis 4-6, 

foliis 1-3. Foliorum vaginae cum setis ca. 1.5 mm 

longis e marginibus superioribus emanentibus; 
NUMBER 11 7 

FIGURE 4.-Habit sketch of Machrolyra tecta: a, Habit of the plant, x y2; b, mature inflorescence 

in its position behind the blade, x 1. Based on Calderdn 2084. 
8 ShIITHSOSIAN COXTRIBUTIONS TO BOTANY 

ligula ca. 0.5-1.2 mm longa, ciliata; petiolus ca. 

4-7 mm longus, 180" tortus; laminae asymmetricae, 

plerumque 10-21 cm longae, 3-5 cm latae, oblongolanceolatae, glabrae, venatione tessellata. Znflorescentia rigida, symmetrica, anguste fusiformis, 

solitaria et in culmo terminalis, 2.7-7 cm longa; 

spiculae unisexuales, 1-florae, approximatae. Spicula 

feminea fusiformis, 9.5-1 1.5 mm longis; glumae 

subaequales, lanceolatae-acutae, glabrae, coriaceae, 

apice leviter curvatae et cucullatae; gluma inferior 

(3-11.5 mm longa, 5-6 nervata; gluma superior 

9.5-1 1 mm longa, 5-7-nervata; lemma 9.7-1 1 mm 

longuni, depressum, anguste lanceolatum, acuminatum, coriaceum, nlaturitate crustaceum, pilis 

longis appressis vestitum; palea 8.5-9.5 mm longa, 

in textura lemma simulans, villosa, ecarinata, 

2-nervata; lodiculae 3, nervatae, 0.7-1 mm longae; 

staminodia 3, ca. 0.33 mm longa; ovarium fusiforme, 

stylo 1, longo, tereti, infra medium antrorsohirsuto, stigmatibus 2; caryopsis hilo lineari, 

embryone basali, I/s longitudinis fructus aequanti. 

Spicitln masczilina lanceolata, subovoidea, 4-5.25 

mm longa, pedicel10 gracili ca, 8 (4-9) mm longo, 

sine glumis, lemmate paleaque in facie et in 

textura glumas femineas simulantibus; lemma ca. 

FIGURE j.-Extravaginal innovation (ei) of Maclurolyra tecta 

with its prophyllum (pr) , as shown breaking through a basal 

bract. Based on Calderdn 2080, x 3.6. 

4-4.5 min longum, glabrum apice scabrum, 

8-lO-ner\.atum; palea 4.4-5 mm longa, lemmate 

longior, ecarinata, nervis 4-6 fortibus; lodiculae 3, 

nervatae, 0.75-1.05 mm longae; staminodia 3, 

minuta; stamina 3, antheris 1-1.5 mm longis. 

Perennial gruss in discrete caespitose clumps, 

usually crowded above and somewhat open below, 

spreading by l'ery short, determinate rhizomes 

emerging from prophyllate buds at a subterranean 

node of the culm or at the base of young shoots, 

internodes of rhizome reduced or up to 1 cm long; 

lateral shoots intravaginal or, more frequently, 

extravaginal, each one producing a new bud in 

rapid succession, but axis at first strongly diageotropic, curved upward and giving rise to a culm; 

bud prophyllum ovoid-lanceolate, short-ciliate at 

the tip, 2-keeled, the keels winged; new aerial 

shoots extending upward ca. 21 (5-26) cm before 

unfolding of the leaves. 

Cu Inis unbranched, erect or geniculate-ascending, 

usually 20-48 cin tall; internodes solid, upon 

drying becoming softer toward the summit, 

sulcate-ridged, the lowermost glabrous, the succeeding ones with minute retrorsely appressed hairs 

in the furrows above the middle, almost glabrous 

below; internodes at the base and at the apex of 

the culms short, the intermediate ones (usually the 

3rd) greatly elongated; nodes 4-6, usually more in 

the first shoots succeeding the seedling culm, 

covered by a dense, retrorse, white pubescence, the 

lower ones less pubescent than the upper ones, 

slightly prominent unless geniculate, narrow in the 

center, all gemmiferous; buds solitary above the 

locus of the sheath attachment; flowering culms 

with 1-3 fully developed leaf blades; culms succeeding the seedling developing more than 3 (up 

to 6) leaves, these culms rather small and weak, 

less than 20 cm tall. 

Leaves exhibiting acropetally a progressive strong 

modification in size, shape, vestiture, and degree of 

blade development; leaves at base of the culm 

small, scaly, loose, broadly triangular-acute, 

glabrous, usually broken by root primordia, the 

succeeding ones consisting of the sheath with the 

blade obsolete or reduced to a minute mucro, much 

shorter than the internode, inflated, rounded on 

the back, glabrous, glossy and sulcate, violet; 

midculm sheaths shorter than the internode, 

inflated, glabrous or glabrescent above, the upper 

edge short-pilose to ciliate; blade very reduced or 
NUMBER 11 9 

up to i mm long in the successive leaves, lanceolateacute, margins scabrous; uppermost 1-3 leaves with 

a completely developed blade. Sheaths imbricate, 

longer than the internode, moderately inflated and 

slightly keeled aboi e, sulcate, glabrous on the back, 

with coarse white antrorse or retrorse minute 

bristles on the sides, ciliate along the outer margin, 

with long bristles (setae) ca. 1.5 mm on the distal 

edge on both sides of the petiole. Ligule ca. 

0.5-1.2 mm long, somewhat thick, ochraceous, 

ciliate. Petiole ca. 4-7 mm long, twisted 180", very 

thick in the middle (pulvinate), glabrous on the 

abaxial surface, densely hirsute on the adaxial 

surface, narrowly winged on the margins by the 

decurrent blade, strongly asymmetrically placed in 

relation to the sheath. Blade asymmetric, flat, 

rather stif-F, erect or ascending to horizontal, mostl) 

10-21 cm long, 3-5 cm wide, oblong-lanceolate, 

acuminate above, terminating gradually in a sharp 

tip, asymmetrically rounded at the base, almost 

oblique on one side, glabrous on both surfaces, 

slightly glaucous on the abaxial surface, antrorsescabious on the margins from above the middle 

to the tip; midrib pale and prominent on both 

surfaces, primary nerves 4-7 on each side of the 

midrib, pale and manifest on the abaxial surface, 

less discernible on the adaxial surface; a11 nerves 

connected by transverse veinlets, these manifest to 

superficial view on the abaxial surface, somewhat 

obscured on the adaxial surface. 

Inflorescence rigid, symmetric, narrowly fusiform, 

consisting of more or less densely aggregated groups 

of spikelets; inflorescence appearing solitary and 

terminal to the culm, ascending, slightly nodding, 

more often abruptly curved or bent laterally or 

downward; reproductive bud, related td the main 

flowering axis in its basal portion, developing into 

a very reduced, inconspicuous, lateral shoot, with 

an inflorescence ca. 1 mm long or more frequently 

remaining dormant, its subtending leaf (bract) 

lacking, but the prophyllum well developed, 

membranous, 2-keeled, ca. 8.5-14 mm long, 

enclosing the lateral shoot, basal internode of 

lateral shoot very reduced, 0.63-0.75 mm long; 

basal part of the main inflorescence axis with its 

lateral product covered for almost its whole length 

by the uppermost leaf sheath, the exserted portion 

2.7-i ciii long, the unbranched part extending 

0.2-1 .?I cm beyond, terete, sulcate, densely hispid; 

rachis subtrigonous or angular by the initiation of 

branches, progressively more slender and almost 

glabrous above. 

Spikelets unisexual, dimorphous and 1-flowered, 

closely appressed and uniformly mixed throughout 

the inflorescence; female spikelet subsessile, terminal to a very short lateral branch, the pedicel very 

short, thick, clavate, somewhat flattened and sulcate 

in young specimens, hispidulous below, glossy 

toward the cupulate apex; male spikelet longpedicellate (usually one per female, just below 

it), the pedicel slender, sulcate, scabrous or shortIiispid, straight or basally curved upward, ca. 

8 (4-9) mm long; spikelets both deciduous by 

abscission below the glumes in the female or below 

the anthecium in the male, at maturity the female 

falling first and the male remaining longer in the 

inflorescence. 

Fcrrinle spikelet fusiform, slightly depressed, 

9.5-11.5 mm long; glumes subequal, of the same 

length as, or a little shorter than, the anthecium, 

lanceolate-acute, rigid, coriaceous, increasingly 

indurate toward the slightly curved and cucullate 

apex, smooth, glabrous, short-hispid on the tip; 

lon.er glume 9-11.5 mm long, 5-6-nerved, upper 

gluiiie 9.5-1 1 mm long, 5-i-nerved, the nerves 

prominent, extending to the apex, the median one 

FIGURE 6.-Intravaginal innovation (ii) of Maclurolyra tecta, 

still within its prophyllum (pr) and growing directly upward from within the bract (b) , x 3.6. Based on Calderdn 

2084. 
10 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

quite separate from the lateral ones, connected by 

transverse veinlets, these more noticeable from the 

inside; margins of the glumes inflexed along the 

outer nerves, those of the lower glume embracing 

the upper glume, upper glume lobate at the base, 

embracing the anthecium. Lemma 9.7-1 1 mm long, 

depressed, narrowly lanceolate, acuminate, margins 

slightly separated below, overlapping and completely covering the palea, strongly convolute at 

the indurate apex, coriaceous, increasingly firm, 

crustaceous at maturity, entirely covered by long, 

appressed hairs; nerves weakly manifest on the 

abaxial surface at maturity, usually 7 (5-8). Callus 

very short, ca. 0.25-0.3 mm long with a rim of 

hairs at the base. Palea 8.5-9.5 mm long, of the 

same texture as the lemma, villous throughout, 

compressed on back, not keeled, 2-4-nerved (the 

nerves obscure) , elliptic-acuminate, convolute, with 

a hard inrolled tip, tightly enclosing the flower. 

Axis of the spikelet developed into a short rachilla 

segment between the lemma and the palea, ca. 

0.5-0.75 mm long. Lodicules 3 (rarely 4), usually 

0.5-1 mm long, one median and posterior, the 

other two lateral and anterior, arranged in one 

whorl, the posterior lodicule not attached to the 

palea, rectangular or oblong-elongate, obliquely 

truncate, irregular or a little lobed at the tip, 

moderately thick throughout with a well developed 

vascular system originating from one vascular 

strand which, immediately after entering the base 

of the lodicule, produces 3-5 traces extending to 

about three-fourths of the length of the lodicule 

and connected by lateral branches, the posterior 

lodicule narrower, sometimes a little shorter. 

Staminodes 3, in one whorl at the base of the ovary 

and alternating with the lodicules, small, ca. 0.33 

mm long, bractlike, triangular-obtuse, sometimes 

very reduced and not vascularized. Gynoecium: 

Ovary fusiform, slightly depressed, glabrous, attenuate at its apex; style one, long, terete, slender 

above, a little flat, broad and antrorse-hirsute below 

the middle, the hairy zone up to 2.5 mm long, and 

ca. 1.75 (1.3-1.9) mm above the ovary apex; 

stigmas 2, obtuse, short, and erect when young, 

long and spiraloid at maturity, the adaxial surface 

covered with globose stigmatic proliferations aggregated into short branches, the distal portion of the 

style and stigma longexserted through a very small 

apical opening of the anthecium. Caryopsis tightly 

enclosed by the lemma and palea, free inside, 

chestnut-colored, glabrous, 5.5 mm long and 1.8-2.0 

mm broad, oblong-oval, ventrally flattened, slightly 

conlex on the dorsal side, not sulcate with a rather 

long, basally coiled style, persistent at the apex; 

hilum linear, extending the whole length of the 

caryopsis; embryo basal, small, about one-eighth of 

the total length of the caryopsis; starch grains 

compound. 

Male spikelet smaller than the female, lanceolate, 

subovoidal, depressed, 4-5.25 mm long. Glumes 

not developed or rarely reduced ones present, the 

lemma and palea resembling in appearance and in 

texture that of the glumes of the female spikelets. 

Lemma broad-lanceolate, acute, slightly clasping 

the palea at the base, ca. 4-4.5 (3.5-5) mm long, 

rigid, moderately indurated, glabrous with the tip 

scabrous or minutely pilose; strongly 7 (8-10) - 

nerved, the nerves extending to the apex, 3 or 5 of 

them fused at the apex and forming a slightly 

cuculla te tip, incurved toward the palea. Callus 

ca. 0.3-0.5 mm long, developed between the lemma 

and the palea and covered by the base of the 

lemma. Palea lanceolate-fusiform, subacuminate, 

4.4-5 mm long, exceeding the lemma and of the 

same texture as it, with 4-6 strong nerves extending 

to the apex, not keeled, compressed or slightly 

convex on the back, with the margins overlapping, 

enclosing the flower. Lodicules 3, in one verticil, 

similar to those of the female flower, but a little 

smaller and thinner, ca. 0.75-1.05 mm long, 

vascular traces 3-6, the posterior lodicule usually 

smaller and with 1 vascular trace. Staminodes 3, 

minute, scaly, occasionally developed as a filamentFIGURE ‘i.-hlaclurolyra tecta, spikelet details: a, Partial inflorescence consisting of the female and male spikelets, x 6. 

Glumes of female spikelet, x 3: b, upper glume (external 

biew), c, upper glume (internal view), d, lower glume (external view), e, lower glume (internal view). Lemma of 

male spikelet, x 6: f, external view, g, internal view. h, Palea 

of male spikelet, x 6; i, portion of stigma, greatly enlarged; 

j, base of gynoecium with lodicule and staminode, x 12.5; k, 

lodicules with staminode at the base, x 12.5. Caryopsis, x 6: 

I, hilum side, rn, embryo side, n, lateral view. o, Completely 

developed gynoecium with staminodes at the base, x 6; p, 

young gynoecium, x 6; q, base of young gynoecium showing 

details of hairy zone, x 25; r, lodicule complement of female 

spikelet, x 12.5; s, lodicule complement of male spikelet, 

x 12.5. Anthoecium, x 6: t, front view showing palea exposed, u, back view, v, front view showing lemma enveloping 

the palea and style exserted apically. All drawings based on 

Calderdn 2084. 
NUMBER 11 11 

C b 

Q 

i 

d e 

G 

ob 

f g 

I rn 

h 

B 

n 
12 SMMITHSONIAN CONTRIBUTIONS TO BOTANY 

ous appendage placed between the lodicules and 

stamens and alternating with them. Androecium: 

Stamens 3, anthers oblong, 1-1.5 mm long, 

filaments elongated at anthesis, exserted at the apex 

through a minute opening between the lemma and 

palea. G) noecium often present, rudimentary to 

somewhat deLeloped, bearing an ovule and 2 or 3 

stigmas. 

iLIATERIAL EXAMINED.-Type: PANAMA: Provincia 

de Col6n: Santa Rita, ca. 25 km before Col6n on 

the Carretera Transistmica (Transisthmian Highway). End of the timber road. Abundant in the 

~voods, especially in the ravine and near the stream. 

lnfiorescences hidden beneath the leaves; some rise 

aboie them but remain coxered by the torsion of 

the axis of the inflorescence and that of the leaf 

petiole. Leaves thick, hard, and rigid. Blade 

divergent or horizontal. 9 March 1968, Cleofe‘ E. 

Calderdn 2084 (Holotype: US; Isotypes: BAA, F, 

Addzttonal Collections: PANAMA: Provincia de 

Co16n: Santa Rita, ca. 25 km before Col6n on the 

Carretera Transistmica, timber road. 5 March 

1968, Cleofe E. Calderdn 2080 (BAA, F, K, MO, 

SY, P, US). Santa Rita: ca. 10 km east of the 

Carietera Transistmica by timber road, alt. 300 in, 

ca. 59“45‘TV longitude, 9”21’N latitude, 2 October 

19i1, C. E. Culderdn ant1 R. L. Diesslei 2130 (BAA, 

I;, I(, NO, SY, P, US), C. E. Caldeidn and R. L. 

111 esylm 2132 (seedlings, US). Provincia de Panami: Cerro Jefe, alt. ca. 900 m, 8 March 1968, C. E. 

Caldel-dn 2082 (US). “La Eneida,” 5 km NE of 

Cerro Jefe, alt. 800 m, 29 October 1971, C. E. Caldeiriii and R. L. Dressler 2138 (BAA, F, K, MO, 

K, MO, NY, P). 

SY, P, US). 

Seedling 

Seedlings of iMaclurolgra were found in all stages 

of development around the periphery of the 

parent plants in the forests of Santa Rita, Panama, 

in October of 1971. The parent clumps were still 

blooming vigorously, so that flowering and development of seedlings occur simultaneously. The 

seeds doubtless germinate very soon after they fall 

to the ground. In the olyroid grass, Cryptochloa, 

we have even found seeds germinating while still 

attached to the inflorescence. 

Differences in grass seedlings and their taxonomic 

value were observed by Avdulov (1931), who 

recognized two types based on the shape and position of the first seedling leaf. In his Type I 

(“panicoid grasses”), the first seedling leaf is broad, 

oval or lanceolate, and horizontal or ascending in 

position, 1) hile in his Type I1 (“festucoid grasses”), 

the first seedling leai is long and narrow, and more 

or less vertical in position. 

More recently Kuwabara (1961a) presented a 

classification of grass seedlings in which he recogniretl three types, based on the position of the first 

seedling leaf. These are (1) perpendicular type, 

(2) ascendant type, and (3) horizontal type. The 

first t)pe is found in festucoid grasses, while the 

second is found in eragrostoid and some panicoid 

grasses, and the third type is found in other 

panicoid grasses. 

\Ye hale observed the seedlings of a few other 

species of olyroid grasses-Lithachne pauciflora, 

Olyru Eoreteriszs, Piresza sympodica-and a species 

of the related genus Pariana, and found them all to 

be similar to tliat of Maclurolyra. These seedlings 

cannot be assigned to any of the types defined in 

the literature. 

Although a “bambusoid type” of seedling has 

not been defined, seedlings of various genera of 

bamboos liai e been illustrated, and the seedlings 

of Xluclicrolpru and the bambusoid grasses mentioned aboie, are of the same type. Some drawings 

md Short descriptions of bamboo seedlings are 

found in Arber (1934), Jacques-Felix (1962), and 

hlcClure (1966) . To our knowledge one of the 

most complete descriptions and illustrations of 

bamboo seedlings is that given by Velenovskylj 

(1914) for Bambusa arundinacea and Schizostachyiinz acutzflorum. 

TVe may, therefore, define the “bambusoid type” 

of grass seedling as follows: coleoptile short and 

not elekated from the caryopsis by an internode, 

first two to seieral leaves bladeless or with a reduced blade, first expanded blade broad, ovatelanceolate, horizontal in position. 

The fact that the coleoptile (Figure ~[co]) in 

the seedling of Maclurolyra is not elevated above 

the lemma suggests that no internode was present 

in the embryo where the vascular traces diverged 

to the scutellum and to the plumule, one of the 

features of the bambusoid type of embryo as 

defined by Reeder (1962) . This is unlike the 

situation found in panicoid grasses, for example, 

where such an internode exists and elongates upon 
NUMBER 11 13 

FIGURE 8.--hlaclutolyia tecta seedlings in the field (Santa Rita, Panama): A, three seedlings in 

different positions; B, single seedling arranged to show shape of first developed blade. [bzblade, 

cn=caryopsis, co=coleoptile, l,=first leaf, 1, =second leaf, l,=third leaf (with a completely developed blade) .] Seedlings are part of Calderdn 2132. 

germination, elevating the coleoptile above the 

caryopsis. 

The seedling of iMaclurolyra (Figures 8, 9) has 

at its base a 2-nerved coleoptile, which is the first 

structure to have broken through the caryopsis 

upon germination. While still in the embryo it 

was a sheathing structure that covered and protected the plumule, but is shown here ruptured, a 

condition which came about when the new shoot 

elongated and broke through it. ?he position of 

the coleoptile is next to the lemma at the point 

where it emerged. 

The first and second leaves of the primary shoot 

consist of a sheath and a very reduced ovate blade 

with no separation between the two. The third 

leaf consists of a sheath, a short petiole, and a 

blade-the first expanded blade of the new plant. 

This blade is ovate-lanceolate, symmetrical, 14-18 

mm long, 6-73 mm wide, and horizontal in position. There is a rapid elongation of the first 

internodes, which surpass their sheaths in length 

and leale the nodes exposed. The fourth leaf 

develops soon after the first, has conduplicate 

\ernation, and the blade of this leaf, as all others 

that follow it, is asymmetrical. 

Seedlings of oryzoid grasses exhibit some 

similarity to bambusoid seedlings in the presence 

of leaves with reduced blades prior to the first one 

with a developed blade. However, the first developed blade is linear rather than ovate-lanceolate 

and assumes an ascending rather than horizontal 

position. Kuwabara (1961b) described and illustrated seedlings of two oryzoid grasses-Leersia 

oryzoides and Zizania latifolia-but did not assign 

them to any of his three types. 

The term “first seedling leaf” as previously used 

in grass systematics should now be understood to 

mean “first seedling leaf with an expanded blade.” 

The reason for this becomes apparent when we 

consider the bambusoid or oryzoid seedling in 

which the actual first seedling leaf consists only of 

a sheath or a sheath with a reduced blade. It is 

the seedling leaf that bears the first expanded blade 

that has taxonomic value, and in these groups this 

blade occurs on one of the leaves following the 

first. 
14 SMITHSOSIAN CONTRIBUTIONS TO BOTANY 

FKLW 9.--Seedling of Mnclurolyin tectn, x 3. [ca=caryopsis, 

co=coleoptile, l,=first leaf, 1>=second leaf, [,=third leaf 

(with blade) ; I,=fourth leaf, still unfolded; pr=primary 

loot.] 

Torsion of the Leaf and Inflorescence 

At anthesis, the inflorescences of Maclurolyra are 

usually found behind the subtending leaf blade 

(Figures 3d,f, 4) while most of the young ones 

are in front of it (Figure 3a,b,e). This comes 

about by a twisting of the petiole (Figure 3d) of 

the subtending leaf and also the axis of the 

inflorescence (Figure 3c) , The twisting exhibited 

by the petiole shows that the leaf blade turns 

around the inflorescence along a vertical axis 

changing its position. The axis of the inflorescence 

also moves around at the same time until it is 

covered by the leaf blade. After maturity, the 

inflorescence bends downward (Figure 3e,f) and 

assumes a position of almost right angles to the 

culm. 

In the seedling the petioles of the first leaves are 

not twisted (Figures 8a, 9). In the first few culms 

which develop from the seedling and have three or 

four leaves, the uppermost leaf that subtends the 

inflorescence exhibits a strong twisting of the 

petiole, while in those below, the twisting is less 

evident, and in the lowermost leaf the petiole is 

usually not twisted. This seems to indicate that 

torsion of the petiole is a phenomenon related to 

the relative position of the blade and inflorescence. 

The position of the inflorescence and the subtending leaf, with the latter covering the former, 

suggests that the leaf has a protective function. The 

blade covers the inflorescence at the time of 

anthesis when the stamens and stigmas are exposed 

and perhaps protects the flowers against an excess 

of rain. We have noticed that such a situation 

occurs in other members of the Olyreae where the 

inflorescences are hidden under the leaves, as in 

Diandrolyra bicolor, Raddia costaricensis, and some 

species of Cryptochloa. 

Leaf torsion was the subject of discussion in 

broad-leaved grasses by Arber (1934:289) . Petiole 

torsion has been described in the distantly related 

genus Pharus by Lindman (1899) and Kugler 

(1928), but in the case of this genus torsion takes 

place along a horizontal axis and reverses the 

morphologically lower and upper surfaces of the 

blade. In Mnclurolyra, torsion of the petiole 

occurs along a \ ertical axis so that the morphologically lower and upper surfaces of the blade are not 

really rei.ersed since it is always in an ascending 

position as it moves around the inflorescence. 

Leaf movement in another olyroid grass was 

described much earlier by Brongniart (1860) who 

spoke of “sleep movements” in Raddia guianensis 

[= Strephiurn guianense]. We have also observed 

this phenomenon in plants of Lithachne pauciflora 

where the blades, horizontally held during the day, 

become reflexed at night. This diurnal movement 

occurs at the base of the petiole where the pulvinus 

is located. In many herbaceous bambusoid grasses 

and in bamboos where the leaf complement consists 

of a number of overlapping sheaths, the petiole of 

each ieaf is twisted slightly to allow all blades to 

lie in the same plane, a point commented upon by 

Holttum (1958: 13) . 
SUMBER 11 15 

Leaf torsion appears to be a common phenomenon in the Bambusoideae, although its raison 

d’etre is not the same in all cases. In many cases 

its function is to bring all leaves of a leaf complement into a single plane, in others it is diurnal in 

character, and in others-as in Maclurolyra-it represenis a more permanent twisting which brings the 

subtentling leaf of the inflorescence into a position 

of protection. 

Observations of living plants of Macurolyra over 

longer periods of time will be needed to understand 

more thoroughly what kinds of movements are involved and their biological significance. Concerning 

this subject we fully agree with Arber (1934:292) 

who remarks, “The problem of the extent to which 

torsion and resupination are autonomous movements, and of the degree to which they are influenced by external conditions, such as light and 

gravity, has not been solved with any completeness. 

It is a direction in which further work is needed . . . .” 

Morphology of the Inflorescence 

As is well known, the floral structure of a grass 

consists of one or more flowers inclosed in bracts 

which form a discrete aggregation known as the 

spikelet. For descriptive purposes the spikelet is 

considered to be the unit of the inflorescence. Spikelets are arranged in various ways in different grasses, 

the most common arrangements being the spike, 

raceme, and panicle. These terms, however, are 

borrowed from the descriptive vocabulary of other 

flowering plants in which they refer to the arrangement of individual flowers in an inflorescence. 

In recent years, the study of inflorescence morphology has received greatest attention from IV. 

Troll and his students, and there exists a voluminous literature on this subject, The correct interpretation of the inflorescence, difficult at best in 

other flowering plants, is all the more so in grasses 

where the individual unit is the spikelet rather than 

the flower. This is all the more complicated by the 

fact that the morphological interpretation of the 

spikelet itself is beset by conflicting theories, for 

example whether the ultimate production (gynoecium and ovule) is cauline or foliar in origin, 

In the inflorescences of many flowering plants the 

presence of subtending leaves and prophylla facilitates the analysis of the inflorescence type. The 

inflorescences of the majority of grasses, however, 

lack these subtending leaves and prophylla. Within 

genera of bambusoid grasses many patterns of 

inflorescence exist, some of them complicated systems of ramification, but often with bracts and 

prophylla developed. 

Probably one of the first attempts to describe in 

detail the arrangement of a bamboo inflorescence 

was that made on Schizostachyurn by McClure 

(1934). The subject has also received attention 

from Holttum (1956, 1958), and, more recently, 

an interpretation of a bamboo inflorescence (Melocanna bum busoides) , based on morphological analysis, w25 made by Petrova (1965). In 1970 the same 

author reported on the inflorescence morphology of 

species of the bamboo genera Phy Zlostachys, Pseudosasa, and Sasa. 

We have attempted to interpret the inflorescence 

of Maclurolyra and some of its allies according to 

the system of Troll, as basically presented in his 

treatise of 1964. We are especially grateful to him 

for the assistance he gave in the interpretation of 

the inflorescences of the olyroid group of grasses 

which he and H. IVeber examined during Calderbn’s visit to their laboratory in Mainz. 

Because of the great diversity of inflorescence 

patterns encountered in genera of the Bambusoitleae and their systematic value, we feel that it is 

extremely important that particular attention be 

paid to them. In the following descriptions of the 

inflorescences of Maclurolyra and related genera, 

we are employing the terminology of Troll (1950, 

1958, 1964). Because these terms have not yet been 

commonly applied to grasses, we feel that the following definitions of these terms, as we apply them 

to the Olyreae, will be useful in understanding the 

discussion which follows. In order to avoid confusion and allow the reader to make comparisons 

with the published inflorescence schemes of Troll, 

we are retaining the German abbreviations both in 

our descriptions and schemes. The original German 

terms and their abbreviations appear in parentheses 

in the following definitions. 

PARTIAL INFLORESCENCE (P J, Partialinporeszenz) : 

A series of flowers (or spikelets) terminating the 

main shoot and the successive secondary floral axes 

produced by the first. These partial inflorescences 

are the so-called panicles or racemes in the tradi- 
16 SMITHSOXIAN CONTRIBUTIONS TO BOTANY 

A B C D 

FIGURE 10.-Schematic of a dissection of a sjnflorescence of Olyra latifolia: A, front and B, 

lateral ciews of the base of the synflorescence after removal of the uppermost leaf of the main 

culm; c, front and D, lateral iiew of the same s)nflorescence with the first prophyllum removed. 

[cxmain culm, i,=first internode; i,=second intelnode, l=uppermost leaf of the main culm, 

nl= first node; n,=second node, nc=node of the main culm, PJ,=first partial inflorescence, 

PJ,=second partial inflorescence, PI3= third partial inflorescence; $r,=first prophyllum, pr. 

=second prophyllum.] 

tional systematic descriptions of the floral systems of 

the Olyreae. 

COMPLEX INFLORESCENCE (Komplexe Znfloresze772): .4 general descriptive term which refers to 

any type of compound inflorescence, but which implies no morphological connotation. 

BRACT (b, Brakt) : The subtending leaf (H, 

Hochblatt) in the axil of which a floral bud or 

floral shoot is found. This bract may be a reduced 

foliar appendage or may have the appearance of 

a normal leaf with a sheath and a developed blade 

PROPHYLLUM (vb, Vorblatt): The first foliar organ of a lateral shoot, usually bikeeled. 

FLORESCENCE (Floreszenz): The series or group 

of flowers at the end of a shoot. In the typology of 

the synflorescence of Troll, florescence is the equi- 

(L, Laubblatt). 

valent of the descriptive term “partial inflorescence.” 

MAIN OR PRIMARY FLORESCENCE (HF, Hauptfloreszenz): The group of flowers, or florescence, 

found at the end of the main shoot. 

COFLORESCENCE (CF, Coporeszenz): Any lateral 

florescence below the main one. 

PARACLADIUM (Pc,Parakladium): The shoot (s) 

arising from the main axis immediately below the 

basal internode of the main florescence, at the end 

of which the coflorescence (s) is found. The paracladia repeat the structure of the main axis. 

SYNFLORESCENCE (Synfloreszenz): The whole floral 

aggregation in a plant, i.e., the system of the main 

florescence with its coflorescences. 

SUPPLEMENTING ZONE (BZ, Bereicherungszone): 

That part of the main shoot, below the main flores- 
NUMBER 11 17 

cence, in which paracladia are produced, thereby 

supplementing or enriching the flowering system 

of the plant. 

INHIBITION ZOKE (HZ, Hemmungszone): The 

purely vegetative part of the main shoot below the 

synflorescence in which the buds do not develop 

under normal circumstances. 

IN~OVATION ZONE (JZ, Znnovationszone): That 

part of the axis in which buds give rise to new 

aerial shoots (innovations). 

iVe shall first discuss the main system of ramification of the flowering system. In most of the 

Olyreae several inflorescences are borne in succession from a node either terminal to tlie main culm 

or terminal to a branch. This assemblage of inflorescences has the appearance of a single raceme 

or panicle since the indi\ idual inflorescences emerge 

close together, the lower part of their axes tightly 

appressed within the uppermost sheath of the culm 

in which they are inclosed. 

In Olyra latifolia, as in many other species of 

this genus, the occurrence of spikelets is restricted 

to the uppermost nodes of the main culm and 

lateral branches when these are produced. The 

growth of the main culm and of the lateral branches 

is limited by the production of spikelets. The distal 

node of the culin or of a iegetative branch produces 

a leaf, usually with a completely developed blade. 

The meristematic shoot apex rapidly continues its 

growth and develops a terminal inflorescence, in 

the case of Oly-n iatifolin with the appearance of 

a “panicle.” This first floral production is in fact 

the first partial inflorescence of a series of two to 

several. From the distal node of the culm, and at the 

base of the primary or main inflorescence, a second 

one is borne (Figures 10a, b, llb). This second 

partial inflorescence develops from a lateral floral 

bud in the axil of the uppermost leaf. The lateral 

floral branch has a very well-developed proph)lluni, 

which is addorsed to the axis of the primary inflorescence, is two-keeled, and incloses the newly 

developing inflorescence. Shortly afterwards this 

floral bud develops a second inflorescence (Figures 

lOc, d, lib), the initiation of a third one taking 

place at the base of this secondary axis. The third 

inflorescence, like the second one, is inclosed within 

a prophjllum which completely envelops it, but no 

trace of a bract is found at its base. The succeeding 

partial inflorescences continue to develop in the 

same fashion. A shortening of the basal internode 

occurs in Olyia latzfolza and in the several species of 

the Olyreae that we have studied so far. In each 

partial inflorescence the distal internode, or epipodium, is quite elongated. 

The main features of the type of inflorescence 

sjstem found in Olym can be summarized as follows: The production of lateral floral branches is 

limited to one. Each partial inflorescence, commencing with the main or first one, produces only one 

lateral floral axis. The second floral axis also produces only one lateral axis, and so on. Thus the 

first branching system of the total inflorescence is 

monochasial, representing a complex inflorescence 

oh the cyniose type. The partial inflorescences of the 

first order are also complex inflorescences in themselves but of a different type. It is outside the scope 

of this paper, however, to present a detailed analysis 

of the partial inflorescence of 0l)ra latzfolza. We 

can, nei ertheless, refer to the partial inflorescence 

‘is a ptrnlczr/odllcm, according to Troll (1967:94, 

1968: 105). 

We feel that the term synflorescence (Troll, 1950: 

388, 1961) slloult~ be used to designate the total 

series of infloi escences. Partial inflorescences of the 

first ordei are the individual floral axes where the 

spikelets take the place of single flowers. A more 

precise teiinlnologi could be used, but according to 

Troll (1964) only in a typological analysis based 

on homologies. 

In Bulbulzis, another genus of Oljreae, the bracts 

or subtentling leaves are present and consist of a 

sheath and a sinall blade. In this genus the main 

culm terminates in an inflorescence, the axis of 

which exhibits a structure much mole complicated 

tlian that 01 Olyn (Figure llc). At the basal node 

of tlie main floral axis is found a bract in the axil 

of which occurs a bud, inclosed in its prophyllum. 

This bud does not develop into a lateral floral 

branch as in the example described above. Distal 

to this node, 011 the same lateral axis, and separated 

b) a fairly long internode, is found another node 

which bears a bract. This bract, like the other ones 

found at the base of the first partial inflorescence, 

consists ot a completely developed sheath and reduced blade. The second partial inflorescence 

emerges liom the axil of this second bract. At the 

I~se of this second partial inflorescence there is also 

a prophyllate bud which remains dormant but no 

bract is found. The lateral branch elongates into an 
18 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

B 

FIGURE 11.-Schematic of the synflorescences of A, Maclurolyra tecta; B, Olyra latifolia; and c, 

Bulbulus nervatus. [bzbract, PJ=partial inflorescences of successive orders (1-4)’ vb=prophyllum.] 

internode and the next node repeats the same construction, The production of partial inflorescences 

in Bulbulus is not so prolific as it is in Olyra latifolia. Usually it forms only three or four partial 

inflorescences of the first order. 

If we now turn to Maclurolyra we encounter a 

pattern of inflorescence somewhat similar to that of 

Olyra latifolia but one which is much simpler 

(Figure Ila). Both differ apparently in the construction of the partial inflorescence itself, i.e., in 

the arrangement of the spikelets. In Maclurolyra the 

synflorescence is terminal to the main culm. At the 

base of the main floral axis a bud within its prophyllum is found. In some specimens we have found 

only a rudimentary inflorescence about 1 mm long. 

The prophyllum is well developed but no bract is 

found; the proximal internode is also very short 

and the distal internode very long. 

In Olyra latifolia, Bulbulus, Maclurolyra, and in 

most of the Olyreae, the axis of every partial inflorescence of the first order consists of a very short 

basal internode and a long distal internode, separated by a node. This is the first node of the lateral 

branch and the one that bears the prophyllum. The 

absence of bracts and the presence of welldeveloped prophylla seem to be general features of 

most of the genera and species of the tribe. 

The first-order ramification of the synflorescence 

of Olyra latifolia is moderately simple. That of 

Bulbulus, on the other hand, is more complex, 

although its pattern still corresponds to that of 

Olyra. A less complex system is found in Maclurolyra where only one partial inflorescence, the main 

one, develops without further ramification. 

The main culm of Maclurolyra does not produce 

lateral vegetative branches, whereas in Olyra latifolia such production is very frequent. In these 

cases, the pattern of ramification of the synflorescence appears to be like that of the branching at a 

node of the main culm, a feature which was observed in the genus Bambusa by Holttum (1958: 

Turning now to the structure of the partial inflorescence of first order, some similarities between 

those of Maclurolyra and Bulbulus are encountered. 

The female spikelet in Maclurolyra is subsessile 

17-1 8). 
SUMBER 11 19 

and the male spikelet is longpedicellate, the latter 

sometimes overtopping the female. It is the female 

spikelet, however, which terminates the reduced 

lateral branch, with the male spikelets borne in a 

position below it. Usually only one male spikelet is 

found at the base of the female, i.e., in a monochasial fashion. The main axis of the inflorescence 

terminates in a female spikelet whose presence is 

sometimes obscured by several (4-6) male spikelets. 

This same situation also occurs in the partial inflorescences of Bulbulus, but these are more reduced 

and consist of only two or three pairs of spikelets. 

In the typology of the inflorescence, Troll (1964) 

recognizes two basic types, the polytelic and the 

monotelic. In the polytelic type of inflorescence, a 

multiflowered florescence is found at the apex of 

the main floral axis. At the end of each lateral 

branch below the main florescence a similar florescence, designated as a coflorescence, is found. On 

the contrary, in the monotelic type, a single flower 

(E, Teyminalbliite) is found at the apex of the main 

and lateral axes. 

Troll (1965: 130, 1968: 105) states that the Gramineae, like the majority of the monocotyledons, 

have .i polytelic type of inflorescence. According to 

his interpretation, the individual spikelets are 

referred to as florescences. The terminal spikelet of 

the total inflorescence, because of its special position, corresponds to the main florescence. The 

remaining spikelets, at the ends of lateral branches, 

are considered as coflorescences. 

The polytelic condition refers basically to the 

spikelet structure, especially to that of the multiflowered ones in which the distichous arrangement 

of the floral members is continued by an extension 

of the spikelet axis, the rachilla, or a reduced floret. 

When the spikelets are uniflowered and there is no 

extension of the spikelet axis, the interpretation is 

more difficult. It has been suggested by Barnard 

(1957) that the flower in the Gramineae may be 

regarded as a branch system in which its parts differ 

in origin, some being cauline and others foliar. The 

origin of the ultimate floral production, the gynoecium and the ovule, is the subject of numerous 

controversial hypotheses and involves the interpretation of the whole spikelet structure. 

In considering the type of inflorescence in grasses, 

the common usage of the term does not refer to the 

disposition of flowers on the floral axis but rather 

to the arrangement of the spikelets In the case of 

the Olyreae the spikelets are one-flowered and we 

have never observed a reduced second flower or prolongation of the rachilla. 

In an attempt to describe very briefly the inflorescence of Maclurolyra, according to Troll’s 

typology, the spikelet is treated here as comparable 

to a flower. 

Figure 12 is a schematic representation of an 

entire plant of Maclurolyra tecta. The plant may be 

divided into three zones: (1) an innovation zone 

(JZ) from which the new shoots are produced from 

the base of the main culm and the nodes of the 

rhizome; (2) an inhibition zone (HZ), representing 

the vegetative zone of the main shoot where the 

axillary buds (which are found at every node) do 

not produce new paracladia; and (3) a supplementing zone (BZ) which refers to the part of the main 

shoot from which the paracladia (Pc) arise. The 

total system of florescences, or synflorescence, is 

formed by a “main florescence” (HF) and several 

coflorescences (CF) below. The main florescence is 

composed of a single female spikelet-which occupies the uppermost position-and 4-6 male spikelets 

below it. Below the basal internode (GJ:Grundinternodium) of the main florescence several paracladia arise, each one repeating the structure of the 

main florescence, but at a reduced grade. The paracladium of each coflorescence is extremely short 

and, as in the main florescence, bears a female 

spikelet in its upper part. Just below the female 

spikelet is found only one male spikelet. 

The main axis of the synflorescence in Maclurolyra terminates in a spikelet as do each of the 

paracladia. In the analysis of the grass inflorescence, 

which is based on the spikelet instead of the flower, 

the inflorescence of Maclurolyra would be termed 

monotelic. If a typological analysis were made of 

the spikelet itself, the same conclusion would be 

reached, for the spikelet of Maclwolyra contains 

but a single flower which terminates the axis and 

beyond which there is no rachilla extension nor 

further production of flowers. 

Troll (1968), however, considers the grass inflorescence to be polytelic, which is the condition found 

in the majority of monocotyledons. This is based on 

the fact that the muItiflowered spikelet has the 

potential for further floral development, as shown 

by terminal rudimentary flower (s) or an extension 

of the rachilla. The uniflowered spikelet has been 

considered to be derived from the multiflowered 
20 SXfITHSOSIAN CONTRIBUTIONS TO BOTANY 

spikelet by reduction, as clearly seen in the case 

of Calamagrostis, for example, where tlie axis 

(rachilla) extends beyond the single floret. 

TVe might therefore ask whether the synflorescence 

of Mgclurolyra, along with that of other members 

HF 

GJ 

Y 

BZ 

HZ 

FIGURE 12.4chematic of Maclurolyra tecta. [BZ=supplementing zone, CF= coflorescence; GI= basal internode of the 

main florescence, HF=main florescence, HZZinhibition 

zone, JZ=innoiation zone, Pc=paracladium.] 

of the Olyreae, is indeed monotelic, or if it represents a form oT tlie polytelic type. Troll (1968:105) 

has recorded exceptions to polytely in other monocotyledonous families, such as the Scheuchzeriaceae, 

Juncaginaceae, Alismataceae, and Burmanniaceae. 

TVeberling (1965:220) has pointed out that when 

exceptions occur in a polytelic family, the more 

primitive genera exhibit a monotelic type of synflorescence. Among the dicotyledons, for example, 

Sambucus and Viburnum have monotelic inflorescences while those of the more advanced genera of 

the same family (Caprifoliaceae) are polytelic. If 

exceptions to polytely do occur in the grass family, 

we should perhaps not be surprised to find them in 

the less advanced genera. 

We consider our analysis of the svnflorescence of 

iMaclurolyra as tentative only. Further studies, especially developmental, of the inflorescence of this 

genus and the other genera of the tribe, are needed 

before our conclusions here can be substantiated. 

Floral Features 

LODICULES 

Taxonomic significance has been given to lodicules on the basis of several studies made from the 

point of view of morphology, anatomy, and ontog 

eny. Recently, some taxonomists have summarized 

the results of these investigations. Stebbins (1956) 

recognized four lodicuie types: bambusoid, festucoid, panicoid, and chloridoid. Decker (1964) reported the previously unpublished conclusions of 

Reeder, who had also found four types: bambusoid 

(bamboos and a few related genera), festucoid, panicoid (Paniceae, chloridoid-eragrostoid, arundinoiddanthonioid, and the centothecoid groups of 

grasses), and a fourth type found in the Meliceae. 

Tateoka (1967) described the structure of lodicules 

of Aristida, Stipa, and the tribe Ehrharteae. Hsu 

(1965) pointed out several distinctive features in the 

lodicules of Panicum. Tateoka and Takagi (1967) 

described the anatomical features of the epidermis 

of lodicules, including those of several tribes of the 

Bambusoideae. Anatomical studies on bamboo 

lodicules were also reported by Takagi (1964, 1967, 

1968) and Dobrotvorskaya (1962). 

It should be noted that lodicules show a strong 

change in their thickness depending on whether 

observed in the fresh, fixed, or in the dried condi- 
SUhiBER 11 21 

tion. In the case of dried specimens, lodicules were 

examined prior to treatment with a wetting agent 

(in this case Aerosol OT Solution). Although the 

lodicules became softer they did not regain their 

normal texture but rather appeared thin and membranous. Those of Olyra latifolia have been reported by Hsu (1965:94) as “papery,” a description 

probably based on herbarium material. In all of 

the preserved material of 0. latifolia that we examined the lodicules were fleshy. 

Butzin (1965:35), in his anatomical description 

of the spikelet of Olyra cordifolia, pcinted out that 

the posterior lodicule is fused at its base with the 

palea. In our studies of olyroid grasses (Calder6n 

and Soderstrom, 1967) we found that in several 

species of Olyra, Piresia, and Cryptochloa, the back 

lodicule becomes detached at a higher level than 

the other two and shows a certain degree of fusion 

with the palea. A similar condition seems to prevail in the bamboos in which, according to McClure (1966: 114), the posterior lodicule is addorsed 

to the palea. 

The lodicules of Maclul-olyi a (Figure 7j,k,r,s) 

possess a number of features which are in agreement with the already-established “bambusoid” 

type. The number of three, the size, and the degree 

of vascularization are unquestionably bambusoid 

features. However, the lodicules of Maclzirolym, 

along with those of the Olyreae, diverge from 

those cf the bamboos in their shape and anatomical 

features of the epidermis. Microhairs, stomata, and 

siliceous cells, which are found in the epidermis of 

bamboo lodicules, are lacking in Maclurolyra and 

the Olyreae (so far with the exception of Olym 

latifolia whose lodicules sometimes possess microhairs along the upper margin). 

The shape of the upper margin (more or less 

truncate), the vascularization, and the texture of 

the lodicules of iMaclzirolyra and the Olyreae resemble more those of the panicoid type. But, on the 

other hand, they differ from panicoid lodicules in 

that they are three in number, not plicate, and are 

usually larger in size. 

The following combination of features allows us 

to establish the “olyroid” type of lodicule. We consider this to be a subtype of the bambusoid type 

of lodicule, and is characteristic of genera of the 

Olyreae, including Maclurolyra: lodicules three in 

number, more or less oblong with an irregularly 

truncate apex, not plicate, fleshy throughout with 

well-developed vascularization, epidermis lacking 

stomata, siliceous cells, and microhairs (except in 

rare instances where they occur along the upper 

margins). 

STAMINODES 

In genera of the Bambusoideae, the occurrence of 

staminodes is rather frequent. It is interesting to 

find them reported for two herbaceous African 

genera with bisexual flowers, Puelia and Atractocatpa (Jacques - Felix, 1962: 118-119; cf Clayton, 

1966, 1967). Holttum (1958:22-23) recorded for the 

Asiatic bamboo, Schizostachyum, the occurrence of 

transitional forms between stamens and lodicules 

and drew attention to this phenomenon as evidence 

of the petaloid nature of lodicules. 

Staminodes have also been observed by several 

investigators in the unisexual flowers of genera 

belonging to the Olyreae. Stapf (1906:204) described Diandrolyra bicolor as having female flowers 

with two staminodes only, the third aborted. Pilger 

(1915: 167) mentioned the presence of three staminodes in female flowers of Buergersiochloa. Butzin 

(1965:35) found the same situation (three nerveless 

staminodes) in the female flower of Olyra cordifoZia. 

In our investigations we have found staminodes 

in several species of Olyra, Cryptochloa, Bulbulus, 

and others. In Diandrolyra we found the staminodes 

to be vascularized. 

Pariana has been described by Doell (1883:331) 

as having five lodicules in both the female and the 

male flowers. Bentham (1881:24) gave a different 

interpretation to the five lodicules of the same 

genus; for him they were rudimentary staminodes. 

Butrin (1965:36) gave an account of the female 

flower of Pharus glaber. He found five rudimentary 

structures around the ovary, two of them considered 

as small lodicules and the remaining three as a 

verticil of stamens. 

Staminodes are always present in the female 

flower of Maclurolyra (Figures 7j,k,o, 13a,b,e,f) and 

frequently also in the male. In the former case 

they appear as three scaly formations which are 

sometimes well developed, are arranged in a single 

yerticil, alternate with the lodicules, and are situated at a higher level, just below the gynoecium. In 

this particular case the use of the word “staminode” 

seems most appropriate as these structures seem to 

represent a vestige of the stamina1 verticil which is 
22 ShfITHSONIAN CONTRIBUTIONS TO BOTANY 

missing. In the male flower the designation of these 

structures is more difficult and depends on interpretation. On one hand they could represent an 

atrophied verticil of stamens, based on the hjpothesis that the primitive grass flower has six stamens, 

alternating in two verticils. According to this hypothesis, a flower of three stamens is derived from 

one of six by loss of the internal verticil (Arber, 

1934: 120, 140). In Macluiolyra the reduction seems 

to have affected the external whorl, a situation 

which does not corroborate such an hypothesis. On 

the other hand, one could assume that these structures represent a rudimentary internal verticil of 

lodicules. Taking into consideration the typical 

floral diagram of the Monocotyledonae, Arber 

(1934: 149) felt that the lodicules in the Gramineae 

iepresent the members of the interal verticil of a 

perianth of two verticils in which the external one 

has been lost. In the male flower of Macluiolyra 

these scaly formations are found between the lodicules and stamens. Arber (1927) described in detail 

the frequency of structures (appendages) intermediate between lodicules and stamens in hermaphrodite flowers of several Bambuseae, which she 

referred to as “stamen-lodicules.” In order to facilitate the description of these structures in the 

present paper, the term “staminode” is used, but 

this is not meant to imply any morphological interpietation. IVe consider it premature to assign them 

definitely to one or the other structure at this time. 

GYKOECIUM 

DEvELoPMENT.-During the course of its development the gynoecium undergoes progressive changes 

in size and shape. In its early stages, when it is 

about 5 mm long, it has the shape of a short bottle 

and the ovary is ovoid or nearly spherical with very 

thick walls (Figure 13a,b). The style is almost conical with two short, blunt, erect, closely appressed 

stigmatic branches. At this early stage there are no 

hairs on the style, In a later stage of development, 

the bare of the style immediately above the apex of 

the ovary is covered by hairs on the front and back 

surfaces (Figure 7p,q), with the narrow sides glabrous. A rapid increase in length takes place in the 

style and later in the stigmatic branches, this occurring mainly at the base of the style and above the 

hairy zone. This elongation causes the hairy zone to 

be displaced upward (Figure 70). In a well developed gynoecium-even prior to fecundation-the 

style is composed of a proximal glabrous zone of 

about 1.3-1.6 mm long, a median one about 1.8- 

2.4 mm long with hairs, and a distal one which is 

slender and glabrous (Figure 70). The stigmatic 

branches also enlarge rapidly and increase in 

length. At maturity the gynoecium has elongated 

considerably and has a style 8-12 mm long. 

HAIRS OF THE STYLE.-When the gynoecium has 

reached maturity, the hairs of the style are also completely developed. This area is densely covered for 

the nost part by long macrohairs (Figure 15b,h) 

with thick walls. The hairy zone in the upper part 

of this zone terminates in a small extension covered by short marcrohairs or hooks (Figures 14a, 

15a,g.). 

hlicrohairs and long multicellular (4-celled) 

hairs (Figure 15c) are also present on the style, as 

observed under high magnification. They are found 

mostly at the base of the hairy zone and between 

the macrohairs. Most of them are tricellular 

(Figures 14b; 15e) and a few bicellular (Figure 

15d,f). The former are 80-109 microns long, more 

or less uniform in diameter, with the distal cell a 

little shorter than the basal ones and with a rounded or slightly tapered tip. The two basal cells have 

much thicker walls than the apical one. The bicellular microhairs are about 112 microns long, are also 

more or less uniform in diameter, but the distal 

cell is longer than the basal one, and is rounded at 

the tip. It is thin-walled as opposed to the basal 

cell which is thick-walled. 

Intermixed with the macrohairs and microhairs 

are long 4-celled hairs (Figure 15c) which occur 

mainly in the lower half of the hairy zone. These 

measure about 333 microns long, the constituent 

cells are of about equal size, have very thin walls, 

and are pointed at the tip. By customary interpretation ot these terms, such hairs cannot be regarded 

as either macrohairs or microhairs. The distinction 

between both kinds of hairs is based on their size, 

FIGURE 13.-Photomicrographs of the gynoecium of Maclurolyra tectn. [i=integuments, It=lateral trace, nu=nucellus, ovt=ovule trace, ph=phloem, stczstylar core, stm 

= staminodes, te= tracheary elements, vszvascular supply of 

the gynoecium, xy=xylem.] Photomicrographs A, E, and F 

were taken with phase contrast illumination, B with dark 

field, c with bright field, and D with polarized light. Magnifications: A and B, x 125; C-E, ~312; F, ~500. 

24 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

number of cells, and shape of the tip of the single 

or distal cell. hIicrohairs are very small, 2-severalcelled, and the basal cell or cells are thicker walled 

than the distal cell which is thin-walled. Macrohairs, on the other hand, are much larger, singlecelled, and have a uniformly thick wall. Tateoka 

and Takagi (1967), in their discussion of lodicule 

hairs, consider the shape of the hair apex as a distinguishing character. The distal cell in microhairs 

is rounded or blunt at the tip while the apex of 

macrohairs is pointed. 

Multicellular microhairs have been observed in 

the epidermis of lodicules of several species of 

bamboo (Pseudosasa, Chimonobambusa, Sasa, Bambusa, Arundinaria, Pleioblastus) by Tateoka and 

Takagi (1967). Takagi (1967, 1968) reported mircohairs made up of 4-6 cells in some species of Sasa 

and Sinobambusa. These multicellular hairs are regarded as microhairs and most of the illustrations 

show that they are similar to bicellular microhairs 

in that they are small, the basal cell is thick-walled, 

and the two or three apical cells are thin-walled and 

rounded at the tips. 

Microhairs made up of three, four, or several 

cells also occur in the leaf epidermis of some bamboos, but such hairs seem to be most common in 

the epidermis of the lodicules. We have not yet 

found multicellular microhairs of this type in any 

species of the Olyreae. 

The 4-celled hairs found on the style of Maclurolyra are unlike multicellular microhairs in that the 

walls of all cells are thin and the hairs are much 

longer and pointed at the tip. In length they 

approach that of some macrohairs, but differ from 

macrohairs in that they have more than one cell 

and are not thick-walled. Since these 4-celled hairs 

do not correspond to either microhairs or macrohairs, we refer to them as “isoleptoid” hairs in allusion to the equal size of all cells in the hair and 

the fact that each is thin-walled. The name is derived from the Greek words isos, meaning “equal,” 

and leptos, meaning “thin.” We have not encountered isoleptoid hairs or multicellular microhairs in 

any other genus of the Olyreae. Takenouchi (1931a) 

figures multicellular hairs for the epidermis of 

prophylla of many species of Japanese bamboos. 

These cells are pointed at the tip but the measurements he gives show them to be much shorter than 

the isoleptoid hairs of Maclurolyra. Since he does 

not give any details concerning these hairs we cannot assign them to any particular type. 

bamboo gynoecium is usually composed of four 

bundles, one posterior or placental strand, two 

lateral-posterior bundles, and a median-anterior 

one. Five or six traces are also very frequent in the 

bamboos. Arber (1926, 1927) reported ovaries with 

six traces in species of Bambusa, Gigantochloa, and 

Cephalostachyum. 

In iUaclurolyra, the number of vascular traces in 

the gynoecium is three (Figure 13c,d), these arising 

from the single main trace (Figure 13e) which enters the ovary at its base. Of the three traces one is 

a posterior placental strand which supplies the 

ovule (Figure 13c-e). It is represented by an arc of 

vascular elements which terminates shortly after 

entering the ovule. The remaining two small lateral 

bundles run up through the ovary walls, enter the 

style, and pass into the stigmas. Both xylem and 

phloem are present in these bundles (Figure 13d). 

A gynoecium with three vascular traces seems to 

be the general rule for the Olyreae, as we have 

found this condition in several species of Bulbulus, 

Cryptochloa, Olyra, Piresia, and Reitzia. 

OVULE-MORPHOLoCY.-~he ovule is semianatropous or anacampylotropous (Bocquet, 1959), bitegmic, and the micropyle is formed by the inner 

integument. This integument is composed of two 

layers of cells in most of its extension, becoming 

thicker (Figure 16b,c) to form the micropyle which 

covers the nucellus completely. Figure 16b,c, shows 

a partially dissected ovule in which the micropyle 

is seen facing downward. In an early stage of the 

ovule development (Figure 13a,b) the two integuments cover the nucellus. A later stage of development is shown in Figures 13c and 16a-c, where the 

outer integument can no longer be distinguished 

clearly. 

The top of the ovule has a cap-shaped formation 

(“apical formation”) which probably represents 

the outer integument reduced (Figure 16a-d). A 

short strand of tissue (“connecting strand,” Figure 

16 b-d) connects this upper part of the ovule with 

FICLRF 14.-Photomicrographs of Maclurolyra tecta: A, B, 

stFle; c, fusoid cells from preparation of dissociated tissue; 

D, chioniosomes in somatic metaphase in young anther, 2n 

~22; F, simple starch grains of Cephalostachyum burmanicum; F, compound starch grains of Machrolyra tecta. [h= 

hook, rna=small macrohair, tmi= tricellular microhair.] 

Magnifications: A-C, ~600; D, ~1500; E and F, ~450. 

VASCULARIZATION.-The Vascular system of the 

26 

a 

SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 15.4tylar hairs of Mnclurolym tecta: a, Small macrohair; b, large macrohair; c, isoleptoid hair; d, bicellular microhairs; e, tricellular microhairs; j, bicellular microhair; g, hooks; 

h, large macrohair. All drawings ~560. 
NUMBER 11 27 

FIGURE 16.-Photomicrographs of the ovule of Maclurolyra tecta. [afzapical formation, cs- -connecting strand, j=funiculus, izintegument, mi=micropyle, ov=ovule, ow=ovary wall, stc 

=stylar core, vb=vascular bundle.] Photomicrographs A, c, and D were taken with phase contrast illumination, and B with dark field. Magnifications: A-C, ~312; D, ~500. 

a central strand of tissue of the style (Figure 16b-d). 

This central portion of the style is referred to by 

Arber (1934) as a stylar core (Figure 16b-d). However, the nature and interpretation of these structures still remain to be investigated. 

Cytology 

Chromosome counts of bambusoid grasses are not 

so numerous as they are for other grasses. Those 

which have been reported for bamboos indicate 

that most species are tetraploids, based on x = 12. 

Chromosome counts for bamboos appear in widely 

scattered publications, but a couple of references 

which deal solely with bamboos are Janaki Ammal 

(1959) and Uchikawa (1933, 1935). 

A basic number of x = 12 has also been reported 

for the herbaceous bambusoid grasses Neurolepis 

(Gould and Soderstrom, 1970), Pariana (Reeder, 
28 ShlITHSONIAN CONTRIBUTIONS TO BOTAXY 

Soderstrom, and Calderbn, 1969), and Streptogyna 

(Tateoka, 1958b; Veyret, 1958). This same basic 

number has also been reported for Pharus (Reeder, 

Soderstrom, and Calderbn, 1969) and Leptaspis 

(Tatcoka, 1958b), genera allied to the Bambusoideae but which we do not include within the subfamily. 

A basic number of x = 11 has been reported 

for Streptochaeta (Valencia, 1962; Pohl and Davidse, 1971), a herbaceous bambusoid grass, and the 

tribe Olyreae, so far reported for the following 

members: Lithachne pauciflora (Pohl and Davidse, 

1971), Olyra latifolia (Reeder, Soderstrom, and 

Calderbn, 1969; Tateoka, 1962a [as 0. yucatana]; 

Pohl and Davidse, 1971), 0. loretensis (Gould and 

Soderstrom, 1970), 0. obliquifolia (Gould and Soderstrom, 1970) Piresia goeldii (Gould and Soderstrom, 1967), and Raddia costaricensis (Pohl and 

Davidse, 197 1 , although Reeder, Soderstrom, and 

Calderon El9691 gave 2n = 24 for the same species). 

Basic numbers lower than x = 11 have also been 

found in the Olyreae, e.g. x = 10 in Bulbulus 

nervatus (Gould and Soderstrom, 1967), Olyra 

micrantha (Gould and Soderstrom, 1967), and 

x = 9 in Diandrolyra bicolor (Daker, 1968, in 

which a karyological analysis is also given), Dr. 

Pierre Morisset (personal communication) relates 

that x = i (2n = 14) in Olyra fasciculata (based 

on Calderdn 2024, previously unpublished). 

A chromosome count of 2n = 22 (Figure 14d) 

was obtained from pollen mother cells of the typecollection of Maclurolyra tecta. We consider it to be 

a diploid based on x = 11 which basic number, 

in the Bambusoideae, conforms to that of many 

members of the tribe Olyreae. 

Starch Grains 

The taxonomic significance of differences in the 

morphology of starch grains in plants was early recognized by Fritzsche (1834). His work was followed 

by that of others such as Nageli (1858), Harz 

(ISSO), and Reichert (1913). More recently Wagnon 

(1952) made use of starch grain differences in separating the grass genera Bromus and Festuca. An 

extensive study of starch grains, found in the endosperm of grasses belonging to 244 genera (comprising 766 species), was made by Tateoka (1962b). He 

recognized four types of starch grains but felt that 

their use was generally of minor significance in the 

taxonomy of the family. 

Our own preliminary studies of starch grains in 

genera of the Bambusoideae, and especially the 

tribe Olyreae, indicate that they may be of different 

types between genera or between species within a 

genus. We believe that characters of the starch 

grains, used in conjunction with other characters, 

shouid prove to be of systematic value. 

The starch grains of Maclurolyra (Figure 14f) are 

compaund and correspond to Type IV of Tateoka, 

the type which he reported for the bamboos under 

his study, We have found compound grains in 

some genera of the Olyreae (Bulbulus, Olyra, 

Piresiu, Raddia, Reitzia) and in some bamboos 

(Oxytenanthera, Phyllostachys, Sinarundinaria, 

Thyrsostachys). Yakovlev (1950: 154) illustrated compound grains for Olyra latifolia. We have found 

simple starch grains (Type 11 of Tateoka) to occur 

as well in the Bambusoideae a$, for example, in the 

Asiatic bamboo, Cephalostachyum burmanicum, 

shokvn here for comparison (Figure 14e). 

Leaf Anatomy 

In the anatomical and histological descriptions of 

the leaf blade we are following the order used by 

Metcalfe (1960), with minor modifications. These 

include the addition of the description of the 

adax’lal epidermis and, in the transverse section, the 

description of the bundle sheath follows that of 

the vascular bundle. 

THE EPIDERMISES 

ABAXIAL EPIDERMIS (Figure 17): Thick cutinized, 

with well differentiated costal zones above the veins 

and intercostal zones between them. Intercostal 

zones formed by three wide bands, two of stomata 

along the sides of the veins and one of long and 

short e!ements alternating with the stomata1 bands. 

SHORT CELLS: Abundant all over; in the intercostal zone in pairs, over the veins mostly in long 

rows, some in short rows of five or six cells, sometimes in pairs. 

SILICEOUS CELLS: Between the veins transversally 

elongated, narrow and crenate, of the “olyroid” 

type (p. 36) with silica bodies smaller than the cells 

and of approximately the same shape, sometimes 
NUMBER 11 29 

FIGURE 17.-Abaxial epidermis of the leaf blade of lllaclurolyra tecta, x 600. [cczsuberin (cork) 

cell, isc=interstomatal cell, Iczlong cell, mh= biccllular microhair, p=papilla, psc=papilla of subsidiary cell, sbo=silica body (olyroid type) , sco=siliceous cell (olyroid type), 

scs=siliceous cell (saddle-shaped) , st = stoma.] 
SMITHSONIAN CONTRIBUTIONS TO BOTANY 

slightly crenate or narrow in the middle, like a 

narrow oryzoid type of silica body. Siliceous cells 

over the veins large, with silica bodies that fill the 

cells completely, mostly in modified cross-shaped or 

intermediate between saddle-shaped and oryzoid 

tY Pee 

SUBERIK (CORK) CELLS: Between the veins associated with a siliceous cell; very small, lobulate or 

cremate, about the same shape as the siliceous cell, 

sometimes outline obscure; those over the veins 

larger. 

MACROHAIRS: None seen. 

PRICKLE HAIRS and HOOKS: Along the edges on 

the upper half of the blade. 

MICROHAIRS: Bicellular, of the linear type, common in, or mainly flanking, the stomatal bands and 

on either side of the veins, but some in the interstomatal zone as well; frequently bent near their 

bases; distal cell thin-walled; usually uniform in 

diameter throughout their length, and with rounded apices or sometimes only slightly tapering towards a rounded point, with both cells of about 

equal length, but mostly with the distal cell slightly 

longer than the basal cell; hairs 48-66 (mostly 

54-60) microns long; basal cells 20-32 (mostly 

22-28) microns long; distal cells 26-34 (mostly 

28-32) microns long. 

PAPILLAE: Abundant, present both in the stomatal bands and over the veins; rather small, variously shaped, irregularly rounded to triangular, 

with crenate outlines; very thick-walled and cuticularized or silicified; more than one row per cell; 

papillae abundant around the stomata, a variable 

number of them projecting above and overarching 

the individual stomata, thus obscuring the outlines 

of the subsidiary cells and the interstomatal cells as 

well. 

STOMATA: Numerous, occurring in bands of 4-6 

rows of stomata that alternate with each other and 

restricted to the sides of the veins; usually only one 

interstomatal cell separating two stomata; stomata 

with triangular subsidiary cells, each one with two 

rounded-crenate, thick cuticular papillae, the stomatal opening being completely obscured by the 4 

overarching papillae. 

LONG CELLS: In the interstomatal bands with 

thick sinuous walls and devoid of papillae; each of 

the long cells in a single row separated by a pair of 

short cells or sometimes by a microhair; those over 

the veins slightly narrower. 

INTERSTOMATAL CELLS: With concave ends and 

markedly sinuous in outline, the cells rather shorter, some ot them almost cubical; papillae very 

abundant. 

TRANSVERSE VEINLETS: Abundant, very conspicuous, connecting vascular bundles of all types and 

with a parenchymatic sheath, 

ADAXIAL EPIDERMIS (Figure 18): Very cutinized 

with bands of bulliform cells in the interstomatal 

zone and bands of long cells on both sides of the 

veins. 

SHORT CELLS: Abundant, over and between the 

veins, mostly in pairs; a few in rows of 3-5 or 

occasionally more cells, over the large veins. 

SILICEOUS CELLS: Between the veins only of the 

olyroid type, similar to those of the abaxial epidermis; silica bodies smaller than the cells, narrow 

and crenate. Siliceous cells over the veins with 

silica bodies mostly of the oryzoid type and saddleshaped, some of the olyroid type or tending to be 

slightly cross-shaped. 

MACROHAIRS: None seen. 

PRICKLE HAIRS and HOOKS: See Abaxial Epidermis. 

MICROHAIRS: Abundant in the intercostal zone 

adjacent to the veins; of the same type as those 

on the abaxial epidermis; microhairs more numerous in this epidermis than in the abaxial one. 

PAPILLAE: Absent on both long cells and bulliform cells. 

STOMATA: Absent or very occasionally some present in the bands of long cells. 

BULLIFORM CELLS: In bands of 3-5 rows of cells 

wide in the middle of the intercostal zones: inflated 

cells, varying in appearance with the focus, short 

and broad to somewhat circular in outline; with 

very thick and strongly undulating walls. 

LONG CELLS: In bands, on either side of the veins, 

formed by 7-9 rows of cells, each cell alternating 

with a pair of short elements or a microhair; with 

very thick and sinuous walls, sinuations strongly 

marked, more so than in the corresponding cells 

of the abaxial epidermis; long cells over the veins 

narrower. 

THE TRANSVERSE SECTION OF THE LAMINA 

FICURB 19, 20, 21a, b, d 

Leaf blade expanded in transverse section, both 

epidermal surfaces slightly undulated. ADAXIAL 
SUMBER 11 31 

FIGURE 18.-.Adaxial epidermis of the leaf blade of Maclurolyra tecta, ~600. [bc=bulliform 

cell, cc=suberin (cork) cell, Ic=long cell, mh = bicellular microhair; sbzsilica body (olyroid 

type), sc=siliceous cell (olyroid type) .] 

SURFACE with fairly wide ribs with rounded apices 

separated from one another by wide, very shallow 

furrows; the ribs over the large vascular bundles 

slightly more protruding; furrows on each side of 

the midrib most marked. ABAXIAL SURFACE less 

undulating than the adaxial one; ribs of the abaxial 

surface corresponding to the furrows of the adaxial 

surface; the slightly rounded ribs corresponding to 

the bulliform cells and the very shallow furrows corresponding to the vascular bundle units. 

VASCULAR BUNDLE UNITS: Fairly widely spaced 

and ilot conspicuously angular in outline; about 

7-9 first order vascular bundles present on either 

side of the midrib; small vascular bundles in groups 

of usually 5-7 alternating with the first order vascular bundles, FIRST ORDER VASCULAR BUNDLES 
32 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

FIGURE 19.-Transverse section of a blade of Machrolyra tecta through the region of a first-order 

bundle, x 600. [a=arm of arm cell, abe=abaxial epidermis, aczarm cell, nde=adaxial epidermis, bc=bulliform cell, cc=companion cell, fc=fusoid cell, gc=guard cell, is=inner bundle sheath, rnv=large metaxylem vessel, oszouter bundle sheath, pZ=protoxylem lacuna, 

px=protoxylem vessel, szsclerenchyma, sc=siliceous cell, ssc=substomatal chamber, st= 

sieve tube, sto =stoma, sub =subsidiary cell.] 
NUMBER 11 33 

somewhat hexagonal in outline (the “basic type” of 

Metcalfe, 1960); large metaxylem vessels present; a 

ring of fibers encircling the phloem, separating it 

from the xylem, and continuing, without transition, to the inner sheath and the abaxial sclerenchymn girder. SMALL VASCULAR BUNDLES somewhat 

oval or oblong in outline, xylem and phloem well 

differentiated; xylem elements fairly wide in diameter, but no large metaxylem vessels present. 

BUNDLE SHEATH: Double: small vascular bundles 

rvith two complete sheaths, the outer sheath often 

having a slight extension of parenchymatic cells, 

sometimes 1 to 3 cells, connecting with the adaxial 

sclerenchyma; first order vascular bundles with the 
34 ShIITHSONIAN CONTRIBUTIONS TO BOTANY 

outer sheath interrupted abaxially, some first order 

bundles also with a small, 1 or 2 cells wide, adaxial 

interruption; abaxial interruption rather wide. The 

outer sheath in all bundles conscipuous and consisting of parenchymatous cells with slightly thickened walls, rather wide in diameter and containing 

few small chloroplasts. The inner sheath very conspicuous and complete in all bundles although in 

the first order bundles somewhat obscure on the 

abaxial side and merging into the adjacent sclerenchyma. In transverse section cells of the inner 

sheath roundish, much smaller in diameter than 

those of the outer sheath, conspicuously pitted, 

with strongly and uniformly thickened walls. In all 

vascular bundles, but mainly in the first order 

bundles, the inner sheath almost double, having 

the appearance of a thick ring encircling the conductive elements. Vascular bundles of the midrib 

completely enveloped by a sheath of highly lignified 

fibers; sheaths about 2 or 3 cells wide in the lateral 

bundles and about 3 or 4 cells wide in the median 

bundle, Small lateral bundles of the midrib region 

with a complete outer sheath; median bundle with 

outer sheath not clearly differentiated from the 

surrounding ground tissue. 

MIDRIB: Very conspicuous owing to a large, 

rounded and flat-topped adaxial, and a rounded 

and a much smaller abaxial, projection; containing 

near the abaxial side one large median vascular 

bundle and 2 smaller laterals, present on either 

side, sometimes 2 on one side and 1 on the other 

side. The median bundle and one lateral bundle 

connected by girders to the abaxial plate of sclerenchyma, sometimes the three vascular bundles of the 

keel with abaxial girders. The whole group of 

vascular bundles embedded in the mass of largecelled ground tissue of the midrib. A zone, several 

layers thick, of chlorenchyma (arm cells) present 

on either side of the adaxial projection, between 

the ground tissue and the epidermis. 

SCLERENCHYMA: All vascular bundles with small 

adaxial and abaxial girders; those of the small 

bundles being somewhat triangular in shape, the 

abaxial girders slightly larger, about 5 or 6 cells 

wide and 3 or 4 cells high; adaxial girders smaller, 

about 2-5 cells wide and 3 cells high, girders of 

the first order vascular bundles more robust, about 

14-18 cells wide by 2-4 cells high in the abaxial 

side; adaxial girders much smaller, about 6-10 cells 

wide by 3 or 4 cells high, combined girders somewhat anchor-shaped. iMidrib supported by a thick 

and wide plate of sclerenchyma in the adaxial 

projection and a narrower mass of sclerenchyma in 

the abaxial rib; tall and rather narrow girders 

connecting this abaxial plate to the median bundle 

and one lateral bundle. 

MESOPHYLL: Chlorenchyma not radiate, consisting of arm cells and fusoid cells occupying the 

center of the lamina in the intercostal zones. 

ARM CELLS (Figures 21b, 22 c,d): Arranged in 

3 or 4 horizontal layers below the adaxial epidermis 

and 2 or 3 layers above the abaxial epidermis. Cells 

flat, irregularly oblong or rectangular in outline, 

with rounded edges and typical invaginations of the 

cell walls extending to less than half the depth of 

the lumina of the cell; 3-5 projecting, rounded 

folds in each cell. In transverse section of the blade 

the orientation of the arm cells differing in both 

the adaxial and abaxial zones. In the adaxial layers 

most of the cells arranged with the folds or “arms” 

perpendicular to the epidermis, thus, in the sections 

the broad face of the cells showing and the “arms” 

proceeding from the lower edge. In the abaxial 

layers the “arms” parallel to the epidermis and only 

the unfolded, back edge of the cell seen, the outline of the folds appearing by transparence as bright 

circles or rings (Figures 19, 20). The arrangement 

of the chlorenchyma cells tending to be slightly 

irregular in the areas surrounding the vascular 

bundles. Arm cells between two fusoid cells rather 

smaller and with arms irregularly oriented. Chlorenchyma cells of the midrib small, and with arms 

apparently proceeding from all four edges. 

FUSOID CELLS (Figures 14c, 2 1 b,c): Translucent, 

large and conspicuous; a single cell present on 

either side of each of the vascular bundles, the tall 

FIGURE 21 .-Photomicrographs of leaf sections of Maclurolyru 

tecta: A, Midrib of blade; B, transverse section of blade oriented almost vertically (the adaxial side toward the right); 

c, longitudinal section through the mesophyll with the fusoid 

cells appearing in cross-section; D, longitudinal section 

through a vascular bundle, [a=annular thickenings of tracheary element; abezabaxial epidermis; aczarm cell; ade 

= adaxial epidermis; ch = chlorenchyma; f = fibers; fc= fusoid 

cell: gt =ground tissue; insp=intercellular space; iszinner 

bundle sheath; nic=mesophyll chloroplast; os=outer bundle 

sheath; ph=phloem; s=sclerenchyma; ssc=substomatal 

chamber; sto=stoma; xy=xylem.] Photomicrograph A was 

taken with polarized light; B with phase contrast illumination, and c and D with bright field. Magnifications: A, ~125; 

B-D, X600. 
NUMBER 11 35 
36 

edge of the cell in contact with the outer bundle 

sheath; their narrow ends facing each other just 

below the bulliform cells, in the center of the intercostal /ones and separated by 3 or 4 chlorenchyma 

cells; usually 208-237 microns in horizontal and 

22-29 microns in vertical, diameter. 

BULLIFORM CELLS: Alternating with all bundles 

and forming regular groups 3 or 4 cells wide, some 

more nearly fan-shaped, mainly those flanking the 

midrib; the groups consisting of large, inflated and 

thick-walled cells of rather uniform size; groups 

extending rather deeply into the mesophyll to about 

half of the blade thickness. 

OLYROID TYPE OF SILICEOUS CELL 

We have adopted the term “olyroid type” of 

siliceous cell or silica body to refer to this special 

type as found so commonly in the leaf epidermis 

of the Olyreae (Figures 17, 18). We have found it in 

all of the species ot Olyra and related genera which 

we have studied to the present and illustrated it 

previously (Calder6n and Soderstrom, 1967). These 

cells were first recognized in the leaf epidermis of 

Olyra Eatifolia by Grob (1896:48) who called them 

Olyrazellen. These cells could also be designated 

as “crenate-horizontal.” We have assumed that the 

word horizontal or transversal refers to any axis in 

right angle to the main or longitudinal axis of the 

leaf. In this respect our description of the olyroid 

type of siliceous cell differs from those given by 

hletcalfe (1960: xix, xlii), who refers to them as 

“tall, narrow and crenate,” or “crenate-vertical.” 

These cells are not exclusive to the Olyreae, however, as they also occur in the epidermis of many 

species of Pariana (Taka Tateoka, 1961) and in 

some bamboos as well. 

The Bambusoid Type of Leaf Anatomy 

Grass leaf anatomy, as revealed by features of the 

transverse sections and epidermal structure, has 

been the subject of numerous investigations in connection with systematics. The results of these 

studies have led to the establishment of a number 

of anatomical types such as the festucoid, panicoid, 

eragrostoid. The anatomical structure of the leaf 

of Maclurolyra conforms most closely to that of 

Olyra and related genera, traditionally included in 

the tribe Olyreae, the morphological and anatomical features of which we briefly summarized earlier 

(Calder6n and Soderstrom, 1967). Besides Olyra 

and iMaclurolyra, included provisionally in this 

tribe are Btilhulus, Cryptochloa, Diandrolyra, Eknianochloa, Lithachne, Mniochloa, Piresia, Raddia, 

Racldiella, and Reitzia. Related to the Olyreae, and 

sharing many anatomical features, are the genera 

Anomochloa, Buevgei-siochloa, Eremitis, Froesiochloa, Pariana, and Streptoehaeta. 

With some minor variations, the genera listed 

above exhibit most of the features common in the 

leaves of bamboos. The outstanding feature of 

these grasses is their herbaceous nature while the 

bamboos are woody. The anatomical features common to all of the genera, whether herbaceous or 

woody, make it evident that they form a natural 

group within the family and should be included 

in the same subfamily Bambusoideae. For convenience, we refer to grasses of this subfamily as “bambusoid grasses,” and to distinguish the two types 

further, “woody bambusoid grasses” (bamboos) and 

“herbaceous bambusoid grasses.” 

The anatomical and histological characteristics 

of the leaves of bambusoid grasses (mostly bamboos) have received attention from several authors, 

one of the earliest of whom was Karelstschicoff 

(1868). More recent anatomical studies have been 

carried out by Page (1947) and Jacques-Felix 

(1955a). The most extensive studies are those of 

hfetcalfe (1956, 1960). Most of these papers have 

dealt with the species of one genus or a few genera, 

although the number of species of bamboos alone 

has been estimated at about a thousand (McClure, 

1966:288). A number of additional papers can be 

mentioned which deal with the anatomy of bamboos, although the following list does not pretend 

to be complete. Some of these papers contain only 

a few data while others are monographic: Haberlandt (1880, 1882); Giintz (1886); Schwendener 

(1890); Grob (1896); IVendehake (1901); Brandis 

(1907); Krause (1909); Takenouchi (1931a, 

1931b); Ohki (1932); Hayata (1929); Avdulov (1931); Arber (1934); Prat (1931, 1936); 

Porterfield (1937); Freier (1941, 1945, 1959); 

Jacques-Felix (1962); Tuguo Tateoka (1956b, 1957, 

1958a); Tateoka, Inoue, and Kawano (1959); Wu 

(1958, 1960, 1962); Brown (1958); Calder6n and 

Soderstrom (1967). There are several more papers 

on anatomy of the root, culm, and floral parts, 

which are not included here. 
NUMBER I1 37 

Our review of the literature and studies of the 

anatomy of. many bambusoid grasses, both woody 

and herbaceous, indicate that the “bambusoid type” 

of leaf anatomy may be characterized as follows: 

LEAF BLADE flat, often asymmetrical, with a very 

conspicuous midrib, containihg a complex vascular 

system; vascular bundles usually in two lines and 

associated with strongly developed sclerenchyma 

and a ground tissue composed of large cells which 

contain plastids. 

CHLORENCHYMA not radiate, but mesophyll elements (arm cells and fusoid cells) arranged in horizontal layers parallel to the epidermis. 

ARM CELLS arranged in a few layers adjacent to 

both epidermises. 

FGSOID CELLS almost without exception present, 

occurring on both sides of the outer bundle sheath 

and between the arm cells. 

BUNDLE SHEATHS always double and well developed; outer, or parenchyma sheath, composed 

of large cells usually with very few chloroplasts; 

inner, or mestome sheath, conspicuous, with cell 

walls uniformly thickened, sometimes more than 

one layer of cells present. 

SMALL VASCULAR BUNDLES usually not angular in 

outline; sometimes the vertical sides of the outer 

sheath somewhat parallel (the “leptaspis” type of 

Metcalfe, 1960). 

SCLERENCHYMA usually forming adaxial and 

abaxial girders rather than strands; no continuous 

hypodermal strands have been described. 

TRANSVERSE VEINLETS connecting the longitudinal 

vascular bundles almost always present. 

EPIDERMIS with short cells generally in pairs or 

sometimes in short rows over the veins. 

SILICA BODIES over the veins usually saddle-shaped 

but a variety of forms may occur-cross-shaped, oryzoid type, or intermediate forms; silica bodies 

between the veins generally of the same shape but 

transversally narrower or olyroid type. 

MICROHAIRS nearly always present and bicellular 

with both cells of about the same length and uniform in diameter; the distal cell with rounded 

apex; 3- or 4-cellular microhairs may occur. 

PAPILLAE very common and abundant on the 

long cells; frequently some of them bent toward 

(overarching) the stomata and obscuring their outline. 

LONG CELLS with thick and very sinuous anticlinal walls. 

STOMATA usually with low dome-shaped or someVariations in the occurrence and distribution of 

the characters listed above may occur as is to be 

expected in any large group. For instance, Merostachys iiedelzana, as described by hIetcalfe (1956), 

is said to differ from the other bamboos in having 

no well-defined midrib. The same author illustrates 

two other species, Arundinaria murielae and Chusquea abietifolia, with a comparatively simple vascular system in the midrib, a condition which we have 

also noted in our own material of Chimonobambusa 

densifolia. Fusoid cells, which are characteristic of 

the inesophyll of bamboos, were not observed in 

certain species of Phyllostachys. Uniseriate microhairs have been reported for Guaduella oblonga, 

and figured as having 3-6 cells (Jacques-Felix, 

1955a; Metcalfe, 1960); also 3-cellular microhairs 

have been noted for Arundznaria vagans. Brandis 

(1907:80) indicated the presence of soft, pluricellular hairs in the leaf epidermis of Melocanna bambusoides. On the other hand, Jacques-Felix 

(1955a) refers to Atractocar~a as lacking microhairs 

and papillae. In spite of these variations, which are 

exceptional, the leaf structure of the Bambusoideae 

seems to be remarkably homogeneous at the generic 

level. On the whole, the bambusoid grasses have a 

very distinctive type of mesophyll which makes 

them stand apart from all other grasses. 

From the above description, it is clear that bambusoid grasses exhibit certain anatomical features 

which are shared by some genera of the Oryzoideae. 

Members of the tribe Zizanieae Hitchcock (1920:2) 

and the genera Chikusichloa, Hygroryza, and 

Rhynchoryza, like the bamboos, have a complex 

system of vascular bundles in the midrib; mesophyll 

composed of fusoid cells and arm cells, although 

somewhat different; bundle sheath double; and 

epidermis frequently papillose with oryzoid type 

silica bodies and often with threadlike microhairs. 

The resemblance of the bamboos to the Oryzeae, 

with regard to leaf structure, has been pointed out 

by several authors ( de Winter, 1951; Metcalf, 1960; 

Tateoka, 1963; Prat, 1931, 1960; Jacques-Felix, 

195513; Schweickerdt and Marais, 1956). However, 

a sufficient number of differences in the structure 

of the mesophyll cells, midrib, the predominance 

of oryzoid type siliceous cells in the epidermis, and 

the overall gross morphology of the oryzoid grasses 

times triangular subsidiary cells. 
SMITHSOXIAN CONTRIBUTIONS TO BOTANY 

show that, although they are apparently closely related tG the bambusoid grasses, they are a distinct 

group. 

Many bambusoid features are also found in the 

genera Lcptaspis and Pharus, included by some in 

the tribe Phareae and by others in the subfamily 

Pharoideae Beetle, But a number of morphological 

features apparently peculiar to them indicate an 

isolated position in the family. Until we have 

studied them further, we prefer not to assign these 

genera at this time to the Bambusoideae. 

The Vascular Bundle Sheath in Grasses 

Among the features that investigators of grass 

leaf anatomy have considered to be of taxonomic 

significance are the sheaths that suiround the vascular bundles. The characters ot diagnostic value 

taken into account are the occurrence ot one or two 

sheaths, i.e., an inner or mestome sheath (Schwendener, 1890) and an outer or parenchyma sheath. 

When there is only one sheath it is the latter that 

is present. The degree 01 development of the cells 

of the sheaths, the occurrence of chloroplasts in the 

outer sheath, and whether these are of a specialized 

type, also have taxonomic importance. 

A single sheath is generally characteristic of 

grasses belonging to the chloridoid-eragrostoid and 

panicoid groups. The cells of the parenchyma 

sheath in these groups are large and the chloroplasts 

are abundant and of a specialized type. Grasses 

belonging to the festucoid group have two sheaths, 

a well-developed inner sheath and an indistinct 

outer sheath composed of thin-walled cells which 

contain few chloroplasts, these being similar to 

those of the mesophyll cells. Double sheaths are 

also found in-grasses belonging to the phragmitoitl 

group but the outer sheath has been described as 

colorless (i,e., without chloroplasts). Grasses of the 

oryzoid and bambusoid groups possess two welldeveloped sheaths, but there is little information 

in the literature regarding their outer sheath and 

the descriptions themselves are not in agreement. 

According to Tateoka (195613) chloroplasts are 

lacking in the cells of the outer sheath of the Bambuseae, but he presented no further data in support 

of this statement. Brandis (1907) indicated that in 

some bamboos the outer sheath has chloroplasts 

and in others it is colorless. Brown (1958, 1961) 

concluded that the outer sheath in bambusoid 

grasses contains chloroplasts, basing this statement 

on the results ot studies of three genera (apparently 

only one species of each) of bambusoid grasses 

(Arundinaria, Phyllostachys, and Streptochaeta). 

These features of the vascular bundle sheaths were 

emphasized by Brown, who divided grasses into six 

major groups according to leaf anatomy. As a result of relying principally on these characterswithout consideration of many others-his “bambusoid” type includes many genera which are not 

closely related. 

If one takes into consideration characters of the 

leaf epidermis, bundle sheaths, mesophyll arrangement, type of chlorenchyma cells, presence or 

absence of fusoid cells, along with other morphological characters, it is clear that there is no close 

relationship between such grasses as Stipa, Uniola, 

Danthonia, and the Bambuseae, all of which Brown 

included in his bambusoid type. The Oryzoideae, 

which are also included by Brown in his bambusoid 

type, ;Ire certainly near the Bambusoideae, but the 

oryzoid type of leaf anatomy can easily be separated 

from the bambusoid. Similar controversial opinions 

are found in the literature regarding the presence 

or absence of plastids in the outer sheath of the 

Oryzoideae. Duval-Jouve (1875) and Tateoka 

(1956a) refer to the outer bundle sheath of the 

Oryzeae as colorless while Brown (1958) reports 

the same sheath as containing chloroplasts. 

In the species of bamboos which we have studied, 

and in all of the genera of Olyreae, we have observed the presence of plastids in the cells of the 

outer bundle sheath. Even though plastids are 

present, however, they are often relatively few in 

number and usually of a very light green color. 

In Maclurolyra there are two bundle sheaths 

(Figures 19, 20). The outer bundle sheath is composed of rather large, parenchymatous cells with 

somewhat thickened walls. These cells are larger 

in diameter than those of the inner sheath, and they 

I:IT.URI. 22.-Photomicrographs of cellular structures of the 

leaf of ,tlnclurolyra tecta, all taken at ~600: A, Longitudinal 

rection through the outer bundle sheath: B, outer bundle 

sheath cells in a partially dissociated tissue, still attached to 

the bundle, c and D, partially dissociated tissues showing arm 

cells viewed from below and bundle sheath cells, respectively. 

[nc=arm cells, Dsc=bundle sheath cell, ch =chlorenchyma, 

!m=mesophyll chloroplast, osc=outer sheath cell, pzplastids.] Photomicrograph A was taken with bright field illumination, B-D with phase contrast. 
NUMBER 11 39 
40 

are roundish to more or less oval-shaped in crosssection (Figure 21 b). Study of longitudinal sections 

shows that they are fairly elongated although they 

vary in length (Figure 22a). In paradermal preparations the sheath cells are found to be in intimate 

contact with the fusoid cells and their outer tangential wall, when in contact with fusoid cells, is 

undulated (Figure 22b). Bundle sheath cells and 

those cells which extend the sheath on the adaxial 

side of the bundle contain plastids (Figure 22b,d), 

although in less amount than in the arm cells. 

Transverse veinlets (“cross veins”) qe also furnished with a bundle sheath (Figure 23 a-c). As 

seen in partially dissociated material they exhibit 

an entirely different aspect compared with that of 

the sheath cells of the main veins. They are parenchymatous cells tightly appressed to the veinlets, 

narrow, very long and usually with rounded or 

tapered ends. They measure about one-half the 

length of the transverse veinlet. Sometimes 1 or a 

few short mesophyll cells connect two long sheath 

cells in a position toward the middle of the veinlet. 

Usually the sheath is single along the veinlet but 

sometimes is partially double (Figure 23a,b). The 

sheath cells of the veinlet are also supplied with 

chloroplasts which appear to be similar to those of 

the mesophyll. 

As we pointed out in the description of Maclurolyra, the inner sheath is very conspicuous and in 

many vascular bundles double, and seems to be 

devoid of chloroplasts (Figure 19). The inner 

sheath cells, as seen in cross-section, have strongly 

and uniformly thickened walls (Figure 21a,b). 

These features were pointed out earlier by Brandis 

(1907:77). He remarked that the inner sheath in 

bamboos is uniformly present, made up of very 

thick and strongly lignified cell walls, and often 

consists of several layers. Hayata (1929:32) also 

remarked that the inner sheath of the bamboos 

studied by him is strongly developed. We have 

found this feature to be constant in all genera of 

the Olyreae (in those genera with several species, 

at least two or three have been examined); and also 

in Pariana, Streptochaeta, Pharus, and in several 

species of Bambuseae. On the basis of this surveyin which we have observed no exceptions-we find 

it tempting to assume that this feature is characteristic 01 all grasses which belong to the Bambusoideae. 

In the festucoid grasses, as in the bambusoid 

grasses, the inner sheath is well developed. We 

should stress that the two groups are similar in 

having a well-developed inner sheath, but the cells 

which make up the sheaths in each group are quite 

different. The inner sheath cells in the bambusoid 

grasses are uniformly thickened. In the festucoid 

grasses the cells are more strongly thickened on 

their inner tangential and radial walls than elsewhere, appearing in transverse section as U-shaped 

(figured in Esau, 1965:439). 

Recently Bisalputra, Downton, and Tregunna 

(1 969) have recorded, in electron microscope 

studies, the presence of plastids in the cells of the 

mestoine sheath of wheat (Triticum aestiuum), a 

festucoid grass. The plastids were described as 

extremely small and appearing to be similar to 

proplastids. 

Chloroplast Structure and Photosynthetic Pathways 

In recent years the study of chloroplasts of 

Gramineae has received special attention, especially 

in members of the panicoid-chloridoid-eragrostoid 

lines. It has long been known that in grasses such 

as corn (Zea mays), sugarcane (Saccharum oficinarum), and sorghum (Sorghum bicolor), the 

cholorplasts of the bundle sheath differ from those 

of the mesophyll cells, in size, color, and in starch 

formation and storage capacity (Rhoades and 

Carvalho, 1944). 

The fine structure of the chloroplast is also well 

known. The chloroplasts of the bundle sheath are 

different in structure from those of the mesophyll 

cells (Laetsch, Stetler, and Vlitos, 1965; Laetsch 

and Price, 1969). They are larger and lighter in 

color, lack grana or only few are developed, and 

they contain large amounts of starch. Mesophyll 

chloroplasts have well-developed grana and contain 

very small amounts of starch. 

Further research has demonstrated that a close 

correlation exists between leaf anatomy, chloroplast 

FIGURE 23.-Photomicrographs of cellular structure of the leaf 

of Maclurolyra tecta, all taken at ~600: A-C, Paradermal sections through transverse veinlets showing bundle sheath 

cells; D, paradermal section of part of the midrib. [aczarm 

cell, f=fibers, fc=fusoid cell, mrczmidrib cell, pzplastids, 

sc=sheath cells, te= tracheary elements.] Photomicrograph 

A was taken with bright field illumination, B-D with phase 

contrast. 
NUMBER 11 41 
42 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

ultrastructure, and the physiology and biochemistry of photohynthesis (Laetsch, 1969; Tregunna et 

al., 1970). 

In grasses which possess a panicoid type of leaf 

anatomy (corn, sugarcane, etc.) and specialized 

sheath chloroplasts, the photosynthetic COz fixation iollows a pathway in which C,-dicarboxylic 

acids are initial products (Hatch and Slack, 1966). 

These species have been reported to have very high 

photosynthetic rates and an apparent lack of photorespiration, features which are also associated with 

low CO, compensation values (Downton and Tregunna, 1968) and low 1% discrimination. Moreover, a lowering of the oxygen concentration 

around these plants does not enhance the photosynthetic CO, assimilation, 

Grasses which possess a festucoid type of mesophyll zrrangement, on the other hand, are markedly 

different with respect to the above structural and 

physiological features. The carboxylation sequence 

followed by grasses of this group is the conventional 

Calvin cycle where C-3 compounds are the major 

initial products. These grasses have low photosynthetic rates and undergo photorespiration. Furthermore, high COP compensation values have also 

been iound in species of this group. In festucoid 

grasses, the chloroplasts of the sheath cells are similar to those of the mesophyll cells except that they 

are somewhat smaller in size. Small amounts of 

starch are found in the mesophyll as well as in the 

sheath plastids. One of the most recent studies of 

the ultrastructure of chloroplasts in a festucoid 

grass was made on wheat (Triticum aestivum) by 

Bisalputra, Downton, and Tregunna (1969). The 

groups of grasses that possess the anatomical and 

physiological set of properties found in festucoid 

grasses are the following natural groups: festucoid 

(Festuca, Triticum, and allies), phragmitoid (Cortaderia and allies), oryzoid (Oryza and allies), and 

bambusoid (Bambusa and allies). 

The bambusoid group is included here on the 

basis of data of COP compensation (in relation to 

14C labeling of the C-4 compounds) derived by 

Hatch, Slack, and Johnson (1967) from Bambusa 

vulgaris and COP compensation values measured 

by Downton and Tregunna (1968) in an unidentified species of Bambusa. To our knowledge no 

studies have been made on the ultrastructure of 

chloroplasts of bambusoid grasses. 

The striking correlation which exists between 

the type of physiology and biochemistry of photosynthesis, and rnesophyll arrangement, in grasses 

presents agrostologists with important new characters previously unemployed in the systematics of 

the family. It is obvious that the study of the 

photosynthetic apparatus is one of primary importance to the interpretation of the natural lines 

of the Gramineae. Although our own studies have 

been limited by light microscopy, we can at least 

describe the features of the chloroplasts and their 

distribution in the leaf of one bambusoid grass, 

Maclurolyra. In this genus, we have found plastids 

not only in the mesophyll and outer bundle sheath, 

where expected, but also in the cells of the ground 

tissue of the midrib. Although no physiological 

data are available for iMaclurolyra, all evidence 

from its leaf anatomy would suggest the presence of 

a C, pathway of CO, fixation. 

CHLOROPLASTS OF THE BUNDLE SHEATH AND MESOPHYLL.-The chloroplasts of the bundle sheath cells 

are located within the peripheral cytoplasm. They 

are round or ovoid and are approximately 3-4 microns long. These dimensions are somewhat smaller 

than those of the mesophyll arm cells. The bundle 

sheath plastids are very light green in color and 

appear somewhat homogeneous in structure (Figure 

22a). These features can be observed best with 

phase-contrast illumination (Figure 22b,d). On the 

other hand, the mesophyll arm cells are packed with 

chloroplasts (Figures 2 1 b,c, 22a,c,d) which appear 

to be of the common type, i.e., they are greencolored and of a markedly granular structure. They 

measure between 5 and 9 microns and are more or 

less ovoid but tend to vary in their form due to 

pressure upon each other. 

PLASTIDS OF THE GROUND TISSUE OF THE MIDRIB.- 

Presence of plastids in the leaf blade is not restricted to the arm cells and parenchyma sheath 

cells. The cells of the ground tissue, which occupy 

a large portion of the midrib, also contain plastids. 

We have found no account in the literature of such 

FIGURE 24.-Photomicrographs of midrib cells of Maclurolyra 

fecta: A, Ground tissue cells adjacent to the chlorenchyma 

showing transition between them and the plastids of the 

central ground tissue; H, ground tissue cells with plastids; C, 

same as A but under different illumination; D, single cell of 

the ground tissue, [ch=chlorenchyma, mc=mesophyll cell, 

nzrc=midrib cell, nznucleus, p=plastids.] Photomicrograph A taken with bright field illumination; B-D with phase 

contrast. Magnifications: A-C, ~600; D, x 1250. 
NUMBER 11 
44 SMITHSONIAN CONTRIBUTIONS TO BOTANY 

plastids in the ground tissue (frequently referred 

to as “colorless tissue”). The ground tissue plastids 

differ from those of the nearby mesophyll in that 

they are very small and almost translucent (Figure 

24a). The former are roundish in cross-section and 

measure approximately 2.5 to 3.5 microns in length. 

There are relatively few plastids per cell, and these 

occur usually near the walls and sometimes around 

the nucleus. In cross-section (Figure 24b,d) only 

very few of them are seen in some of the cells, but 

paradermal or longitudinal sections revea; their 

presence in all of the cells (Figure 23d). These 

plastids are extremely light colored when observed 

under regular transmitted light. They are more or 

less similar to the bundle sheath plastids and show 

a homogeneous structure. The number of plastids 

per cell and their size and color increase in those 

cells of the ground tissue which are near or adjacent 

to the arm cells of the midrib (Figure 24a,c). This 

gradual differentiation of the midrib organelles 

suggests that these are plastids, probably similar 

to prcplastids. Sections treated with a weak IKI 

solution did not stain, indicating that no large 

amounts of starch are deposited in these organelles. 

We have also observed such plastids in the midrib 

of all of the genera of the Olyreae, Pariana, Pharus, 

Stwptorhaeta, and in several bamboos, as enumerated in the following list. Except for slight differences in size, color, and abundance, all of these 

species have plastids in the ground tissue of the 

midrib: 

Bambusa arundinacea (Soderstrom & Kulatunge 

1774), B. multiplex (Soderstrom (1. Kulatunge 

1603), B. vulgaris (Soderstrom 6. Kulatunge 1763), 

Chimonobambusa densifolia (Soderstrom 6. Kulatunge 1656), Cryptochloa species (Calderdn 2074, 

2083), Dendrocalamus giganteus (Soderstrom 6. 

Kulatunge 1602), Diandrolyra bicolor (Soderstrom 

s.n.), Eremitis monothalamia (Calderdn 2039), Zndocalamus debilis (Soderstrom & Kulatunge 1606), 

I. floribundus (Soderstrom Q Kulatunge 1658), 1. 

walkerianus (Soderstrom (1. Kulatunge 1772), I. 

wightianus (Soderstrom (1. Kulatunge 1608), Lithachne pauciflora (Pohl (1. Calderdn 10136), Ochlandra stridula (Soderstrom 6. Kulatunge 1673), 

Olyra fasciculata (Calderdn 2024), 0. glaberrima 

(Calderdn 2010), 0. lateralis (Calderdn 2092), 0. 

obliquifolia (Cnlderdn 2062), 0. aff. taquara (Calderdn 2087), Oxytenanthera monadelpha (Soderstrom Q Kulatunge 1605), Pariana campestris (Caldeidn 2063), P. lanceolata (Calderdn 2040), Pharus 

species (Soderstrorn L+ Calderdn 1206), P. glaber 

(Cnlderdn 2016), Piiesia goeldii (Soderstrom 1428), 

Piiesia species (Calderdn 2047), Raddia brasiliensis 

(Calderdn 203 l), R. costaricensis (Calderdn 2109), 

Raddiella nann (Calderdn 2009, 2071), Reitzia 

snzithii (Caldeidn 2002), Streptochaeta sodiroana 

(Soderstrom A- Calderdn 1205), and Teinostachyum 

attenuatzim (Soderstrom L- Kulatunge 1657). 

Phylogenetic Position of Maclurolyra 

Probably the best clue to the relationships of an 

unknown grass is found in its leaf anatomy and epidermis. Thus the first step in determining the 

phylogenetic position of Maclurolyra was a study 

of these aspects of the plant. We found its leaf 

blade to contain a mesophyll composed of fusoid 

cells and arm cells arranged in layers parallel to 

the epidermis, two well-developed bundle sheaths 

with the outer one containing chloroplasts, and a 

fairly complex midrib struc ture-with an epidermis 

containing saddle-shaped and olyroid type siliceous 

cells, bicellular microhairs , an abundance of p

lae, and stomata with triangular subsidiary cells. 

Such a leaf structure is characteristic of bamboos, 

a group of grasses traditionally regarded as rather 

distinct within the family, doubtless due to the 

woody nature of their culms and a number of 

morphological features not ordinarily found in 

other grasses. A few grasses with herbaceous culms 

have been studied by other investigators who found 

them to have the same type of leaf anatomy, and 

the suggestion has been made that some might belong to the same subfamily as the bamboos. Our 

comparative studies of the leaf anatomy of Maclurolyra, of a number of bamboos, and of the putatively allied herbaceous genera, have led us to the 

conclusion that all possess a rather homogeneous 

leaf anatomy and should indeed be included within 

the same subfamily, Bambusoideae. The “bambusoid” type of leaf anatomy, which we have attempted to clarify, is found not only in the largest 

of bamboos, such as Dendrocalamus giganteus, 

whose culms may ascend to thirty meters, but as 

well in such Lilliputian members as Raddiella nana, 

whose culms reach no higher than a few centimeters. 

In addition to its leaf anatomy, several other 

features of Maclurolyra recall those which are com- 
&UMBER 11 45 

mon among bamboos: rhizomatous nature, petiolate 

leaf with a broad blade and tessellate venation; 

three vascularized lodicules; hairs on the style; high 

basic chromosome number; small embryo; linear 

hilum. Even the seedling of iMaclurolyra is like that 

of the bamboos, characterized by the development 

of one or more reduced leaves before the first expanded blade, which is broad, ovate-lanceolate, and 

held in a horizontal position. 

The herbaceous condition of the culm of Maclurolyra tecta, its I-flowered spikelets, and monoecious condition, all point to a relationship-within 

the Bambusoideae-to the tribe Olyreae. In genera 

of this tribe, the female spikelets are l-flowered and 

consist of two glumes, an indurate lemma and palea, 

3 lodicules, and a gynoecium with a single long 

style and 2 stigmas. The male spikelet is also 

l-flowered and consists generally of a thin 3- 

nerved lemma and palea, 3 lodicules, and an androecium of 3 stamens, but usually lacks glumes. 

Occasionally the female spikelet contains rudiments 

of male organs in the form of staminodes, and the 

male spikelet contains rudiments of the female 

organ in the form of a pistilodium. 

The spikelet arrangement in Mnclu~oly~a and the 

multinerved condition of the male lemma are repeated in the genus Bulbulus. Both genera are also 

consistent in the presence of a pistilodium in the 

male flower and staininodes in the female flower. 

Separation of sexes, with the concomitant 

monoecious or dioecious condition, is regarded as 

a highly advanced floral character in the angiosperms. The presence of staminodes in the female 

flowers and pistilodium in the male flowers of some 

Olyreae is an indication that they were once bisexual. Although the monoecious condition is found 

in all genera of the Olyreae, it is rare elsewhere in 

the Bam busoi deae. 

It is interesting to note that separation of sexes 

has occurred in the most advanced members of all 

of the large major natural groups of the grass 

family: festucoid group (section Dioicopoa of the 

genus Poa), centothecoid group (Zeugites), chloridoid-eragrostoid group (Buchlomimus, Reederochloa), phragmitoid group (Phragmites), oryzoid 

group (Hygroryza, Luziola, Zizania), panicoid 

group (tribe Andropogoneae, tribe Tripsacaceae, 

Spinifex). Therefore, with respect to the character 

of monoecism, the Olyreae seem to represent an 

advanced line of the bambusoid group. 

Because the monoecious condition is found in 

each natural group of grasses, it must have occurred independently in each line. Considering this 

condition to have arisen only once and to be of 

primary importance, led Roberty (1960:36-37) to 

bring together such widely unrelated monoecious 

genera as Olyia and Zea and to consider them to 

belong to an entirely separate family, the Zeaceae (I). 

Reduction in the number of vascular traces in 

the ovule of bambusoid grasses appears to be an 

indication ot advancement. In the genus Streptochaeta, Arber (1929:41) noted the presence of four 

vascular traces, a condition common in many bamboos. In other bamboos five or six traces have been 

recorded. It is tempting to consider the condition 

of three traces as found in the ovule of Maclurolyra 

and other Olyreae as an advancement over those in 

which the number is larger. 

Maclurolyra tecta is a diploid with a basic number of x = 11, the most common basic number in 

the Olyreae. However, the basic number for the 

subkamil) Bambusoideae is x = 12, with this number reported for the herbaceous genera Pariana and 

Stxptogyna, and for the majority of bamboos. The 

basic number of x = 12 is also found in many 

genera of other grass groups such as the oryzoid, 

phragmitoid, and centothecoid. This supports the 

Iiewpoint of Tzveliov (1969), who states that 

x = 12 is the basic number for the grass family. 

TLveliov further postulates that lower basic numbers in the family are derived from x = 12. 

Within the Bambusoideae, the Olyreae may thus 

be regarded as advanced in terms of their basic 

chromosome number, Although x = 11 is the most 

common basic number we have encountered so 

far in the tribe, we have found numbers as low as 

x = 7. Within the tribe itself, Maclurolyra might 

be among the least advanced genera since it retains 

the basic number of 11. It is interesting to point 

out that most bamboos are tetraploids (2n=48), 

which is the most widespread level of polyploidy 

in the great majority of mature polyploid complexes, according to Stebbins (1971: 162). 

As we stated earlier (Soderstrom and Calderh, 

1971), bamboos probably were derived fom herbaceous ancestors. It is probable that bamboos 

arose as polyploids from diploid herbaceous ancestors, perhaps on more than one occasion. Their 

success as polyploids must certainly be attributed to 
46 SXIITHSOSIAN CONTRIBUTIONS TO BOTANY 

the fact that they are long-lived perennials, with 

strongly developed rhizomes that allow them to 

reproduce vegetatively. Flowering in most bamboos 

is infrequent and when it occurs, sterility barriers 

are often present. 

Most herbaceous bambusoid grasses are diploid 

and flower throughout the year, while most bamboos are tetraploid and flower only once in many 

years. Over a long period of time the former produce countless generations in comparison with the 

latter, a point commented upon by Arber (1934: 

87). This has allowed specialization to occur in the 

spikelet structure of the herbaceous bambusoid 

grasses while the same has apparently occurred to 

a lesser extent in the bamboos. 

Recent studies have shown that angiosperms are 

separable into two groups with regard to their 

photosynthetic carbon metabolism. The predominance of a C:< or C, pathway is associated with a 

set of distinct photosynthetic properties and particular features of the leaf anatomy, chloroplast ultrastructure, and ecology-a correlation which has 

proved to be consistent with taxonomic groupings. 

Data concerning any one of these physiological or 

anatomical characteristics can be used as reliable 

indicators of the dominant carbon fixation pathway 

followed by a plant. In Maclurolyra, for example, 

the presence of a C, metabolism is suggested by 

its bambusoid type of leaf anatomy. This less efficient type of metabolism has also been reported for 

grasses of the oryzoid, festucoid, stipoid, and 

phragmitoid groups, in contrast to the highly efficient C, pathway of photosynthesis found only in 

the most advanced members of the family. 

In conclusion, our studies show that Maclurolyra 

is a genus which belongs to the tribe Olyreae of the 

subfamily Bambusoideae, and apparently represents 

one of the less specialized genera of the tribe. It is 

not surprising that it inhabits rain forests in Panama, an area which is phytogeographically related to 

the ChocG region of Panama and Colombia, the 

latter considered to be one of the ancient forests 

that harbors relic genera (Haffer, 1969). 

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Appendix 1 

GENERA OF THE SUBFAMILY BAMBUSOIDEAE AESCHERSON AND GRAEBNER 

We consider the subfamily Bambusoideae to comprise the genera in the following list. The list is 

the result of our consultations concerning the bamboos with the late F. A. McClure and our own 

studies on herbaceous bambusoid grasses. This list 

is to be considered provisional since we have not 

yet studied representatiyes of each genus. (H) following the name indicates that the genus is an herbaceous bambusoid grass; all others are bamboos. 

Anomochloa (H), A? tlzrostylzdzzim, Arundinaria, 

At127 oostachys, Aulonemza, Banzbusa, Bonia, 

Brach yst ac h y ii nz, B zi e? gel sz oc h 1 oa (H), B u 1 b u 1 us 

(H), Ceplznlostnchyzim, Chimonobambzisa, Chusqiiea, Ctyptochloa (H), Decaryochloa, Dendrocalamus, Dendrochloa, Diandrolyra (H), Dinochloa, Ekmanochloa (H), Elytrostachys, Eremitis (H), 

Fargesia, Froesiochloa (H), Gigantochloa, Glaziophyton, Greslania, Guadua, Guaduella (H), Hickelia, Hitchcockella, Indocalamus, lndosasa, Ling 

nanza, Lithachne (H), Maclurolyrn (H), Melocalamus, iMelocanna, Merostachys, Mniochloa (H), 

Myiiocladus, Nastzis, Seohouzeaua, Neurolepis 

(H), Ochlandra, Olyl-a (H), Oreobambos, Oxytenanthera, Pariana (H), Perrierbambus, Phyllostnchys, Piirsin (H), Pleioblastus, Pseudocoix, Pseudosasa, Pseudostachyum, Puelia (H), Racemobambos, Rnddia (H), Raddiella (H), Reitzia (H), 

Rettbelgia, Sasa, Sasaella, Sasamorpha, Schizostachyum, Semiamndinaria, Shibataea, Sinarundinaria, 

Sinobambusa, Sinocalamus, Streptochaeta (H), 

Stref~togyna (H), Teinostachyum, Thamnocalamus, 

Thy?sostachys, Yushania. 

Appendix 2 

LIST OF MATERIAL STUDIED 

Bambzisa arundinacea. Ceylon: Kandy District: 

Peradeniya. 10 December 1969. Soderstrom 6 

Kulatunge 1774. 

Bambusa multiplex. Ceylon: Kandy District: Peradeniya; Royal Botanic Gardens. 27 October 1969. 

Soderstrom 6 Kulatunge 1603. 

Bambusa vulgaris. Ceylon: Kandy District: near the 

Malwatte Temple. 1 December 1969. Soderstrom 

d. Kulatunge 1763. 

Bulbulus neruatzis Swallen. Surinam: Wilhelmina 

Gebergte. 1 September 1963. Irwin, Prance, Soderstrom, ?;- Holmgren 55321. 

Cephalostachyum burmanicum. USDA (United 

States Department of Agriculture) P.I. (Plant 

Introduction) No. 117530. 

Chimonobambusa densifolia. Ceylon: Nuwara Eliya 

District: Horton Plains. 11 November 1969. Soderstrom d. Kulatunge 1656. 

Cryptochloa, new species. Panama: Prov. de Pan. 

ami: Cerro Jefe. 3 March 1968. Calderdn 2074. 

Cryptochloli, new species. Panama: Prov. de Panaid: Cerro Jefe. 8 March 1968. Calderdn 2083. 

Dendrocalamus giganteus. Ceylon: Kandy District: 

Peradeniya; Royal Botanic Gardens. 23 October 

1969. Soderstrom 6 Kalatunge 1602. 

Diandrolyra bicolor. England: Kew, cultivated at 

Royal Botanic Gardens. November 1967. Soderstrom s.n. 

Eremitis monothalamia. Brazil: Bahia: Municipio 

Ubsitaba. 13 January 1968. Calderdn 2039. 

Indocalamus debilis. Ceylon: Nuwara Eliya District: lower slopes of Pidurutalagala. 3 November 

1969. Soderstrom d. Kulatunge 1606. 

Indocalamus floribundus. Ceylon: Badulla District: 

between Ohiya and Boralanda. 13 November 

1969. Soderstrom & Kulatunge 1658. 

Indocalamus walkerianus. Ceylon: Nuwara Eliya 

District: near Edikatupana. 5 December 1969. 

Soderstrom d. Kulatunge 1772. 

52 
NUMBER 11 53 

Indocalamus wightianus. Ceylon: Nuwara Eliya 

District: summit of Pidurutalagala. 4 November 

1969. Soderstrom S Kulatunge 1608. 

Lithachne paucifloia. Costa Rica. 1966. Pohl cir 

Calderdn 10136. 

Ochlandra stridula. Ceylon: Kegalle District: Arandara. 16 November 1969. Soderstrom L+ Kulatunge 

1673. 

Olyia fasciculata. Brazil: Guanabara: Estrada da 

Ghvea. 3 January 1968. Calderon 2024. 

Olyra glaberrima. Brazil: Guanabara: Rio de Janeiro. 28 December 1967. Calderon 2010. 

Olyra lateralis. Panama: Prov. de Panama: Cerro 

Campana. 13 March 1968. Calderon 2092. 

Olyia latifolia L. Venezuela: Aragua: Maracay. 18 

February 1968. Colderon 2072. 

Olym obliquifolia. Brazil: Pari: Belkm. 29 January 

1968. Calderdn 2062. 

Olyra aff. tayuaia. Panama: Prov. de Panamh: 

Cerro Azul. 11 March 1968. Calderdn 2087. 

Oxytenanthera monadelpha. Ceylon: Nuwara Eliya 

District: near Ramboda. 2 November 1969. Sodeistrom (1- Kulatunge 1605. 

Paiiana campestris. Brazil: Pari: Belem. 2 February 1968. Calderdn 2063. 

Pariana lanceolata. Brazil: Bahia: Municipio Ubaitaba. 13 January 1968. Calderdn 2040. 

Phatus sp. Costa Rica: Puntarenas. 27 June 1966. 

Soderstrom & Calderdn 1206. 

Pharus glaber. Brazil: Guanabara: Rio de Janeiro. 

29 December 1968. Calderdn 2016. 

Piresia goeldii. Colombia: Amazonas: Leticia. 4 

February 1969. Soderstrom 1428. 

Pi?esza, new species. Brazil: Bahia: Santa Cruz 

Cabralia. 18 January 1968. Calderdn 2047. 

Rnddzn biasilienszs. Brazil: Bahia: Municipio Ubaitaba. 11 January 1968. Calderdn 2031. 

Raddia costaricensis. Costa Rica: Prov. de Lim6n: 

Rio Hondo. 28 March 1968. Calderdn 2109. 

Raddiella nana. Brazil: Distrito Federal: Parque 

Municipal do Gama. 21 December 1967. Calderdn 

2009. Pari: Municipio Vigia, Campinha do 

Paiha. 10 February 1968. Calder6n 2071. 

Reztzza smzthii. Brazil: Santa Catarina: Municipio 

BruLque, Asambuja. 8 December 1967. Calderdn 

2002. 

Strcptochaeta sodiioana. Costa Rica: Puntarenas. 

27 June 1966. Soderstrom d* Calderdn 1205. 

Teznostachyum attenuatum. Ceylon: Badulla District: between Horton Plains and Ohiya. 12 November 1969. Soderstrom Q Kulatunge 1657. 
Index to Grass Genera and Species 

4nomochloa A. Brongniart, 36, 52 

Aristida L., 20 

Arthrostylidium Ruprecht, 52 

Arundinaria A. Michaux, 24, 38, 52 

Arundinaria murielae Gamble 

[=Sinarundinaria murielae] 

Arundinaria vagans Gamble, 37 

Atliroostachys Bentham, 52 

Atractocarpa Franchet [ZPuelia 

Aulonemia Goudot, 52 

Franchet] 

Bambusa Schreber, 18, 24, 42, 52 

Bambusa aiundinacea (Retzius) Willdenow, 12, 44, 52 

Bani busa glaucescens (IVilldenow) Siebold ex Munro, 44, 52 

Bambusa multiplex (Loureiro) Raeuschel [=Bambusa glaucescens] 

Barnbusa vulgaris Schrader ex Wendland, 42, 44, 52 

Bonia Balansa, 52 

Brachystachyum Y. L. Keng, 52 

Bronius L., 28 

Buchlominius Reeder, Reeder, and Rzedowski, 45 

Bueigersiochloa Pilger, 21, 36, 52 

Bulbulus Swallen, 17, 18, 19, 21, 24, 28, 

Bulbulus newatus Swallen, 18 (fig.), 52 

36, 45, 52 

Calaniagrostis Adanson, 20 

Cephalostachyum Munro, 24, 52 

Cephalostachyum burmanicum Parker 

and Parkinson, 24 (fig.), 28, 52 

Chikusichloa Koidzumi, 37 

Chinionobambusa Makino, 24, 52 

Chimonobambusa densifolia (Munro) 

Nakai, 37, 44, 52 

Chusquea Kunth, 52 

Chusquea abietifolia Grisebach, 37 

Co? taderia Stapf, 42 

Cryptochloa Swallen, 1, 3 (fig.), 12, 14, 

21, 24, 36, 44, 52 

Danthonia Lamarck and A. P. de CanDecaryochloa A. Camus, 52 

Dendrocalanius C. G. D. Nees, 52 

Dendrocalamus giganteus Munro, 44, 52 

Dendrochloa Parkinson, 52 

dolle, 38 

Diandrolyra Stapf, 21, 36, 52 

Diandrolyra bicolor Stapf, 14, 21, 28, 

Uinochloa Biise, 52 

44, 52 

Ekmanochloa Hitchcock, 36, 52 

Elytiostnchys McClure, 52 

Eiemitis Doell, 36, 52 

Eieniitis monothalamia Doell, 44, 52 

Faigesia Franchet, 52 

k'estuca L., 28, 42 

Froesiochloa G. Black, 36, 52 

Gignntochloa Kurz ex Munro, 24, 52 

Glaziophyton Franchet, 52 

Greslania Balansa, 52 

Guadua Kunth, 52 

Guaduella [as Guadella] Franchet, 52 

Guaduella oblonga Hutchinson ex If. 

D. Clayton, 37 

Hickelia A. Camus, 52 

Hitchcockella A. Camus, 52 

Hygroryza C. G. D. Nees, 37, 45 

Indocalamus Sakai, 52 

Indocalainus debilis (Thwaites) Alston, 

Zn doca la m us pori bund us (Thwai tes) 

Indocalamus walkerianus (Munro) Nakai, 

Indocalamus wightianus (Sees) Nakai, 

Indosasa McClure, 52 

44, 52 

Sakai, 44, 52 

44, 52 

44, 53 

Lreizia oijzoides (L.) Swartz, 13 

Leptnspis R. Brown, 28, 38 

Lingnania McClure, 52 

Z-itiinchne Palisot de Beauvois, 36, 52 

Lithachne paucipora (Swartz) Palisot 

Luziola .A, L. Jussieu, 45 

de Beauvois, 12, 14, 28, 44, 53 

Melocalnmus Bentham, 52 

Melocanria Trinius, 52 

Jlelocanna bambusoides Trinius, 15, 37 

dlerostachys K. P. J. Sprengel, 52 

iMerostach>s riedeliana Ruprecht, 37 

Mniochloa Chase, 36, 52 

MI riocladus Swallen, 52 

54 

Xastus A. L. Jussieu, 52 

Seohouzeaua A. Camus, 52 

Seurolepis Meisner, 27, 52 

Ochlandra Thwaites, 52 

Ochlandra stridula Thwaites, 44, 53 

Olyra L., 2, 15, 21, 24, 28, 36, 45, 52 

Olyia cordifolin Humboldt, Bonpland, 

02yra fasciculata Trinius, 28, 44, 53 

OIyra glaberrima Raddi, 44, 53 

Olyra lateralis (J. S. Presl ex Nees) 

Olyra latifolia L., 16 (fig.) , 17, 18 (fig.), 

Olyra loretensis Mez, 12, 28 

Olyra micrantha Humboldt, Bonpland, 

Olyra obliquifolia Steudel, 28, 44, 53 

01yra taquara Swallen vel aff., 44, 53 

01jra yucatana Chase, 28 

Oreobambos K. Schumann, 52 

Otyza L., 42 

Oxytenanthera Munro, 28, 52 

Oxytenanthera monadelpha Alston 44, 53 

Panicum L., 20 

Pariana Aublet, 12, 21, 27, 36, 40, 44, 

Pariana canipestris Aublet, 44, 53 

Pariana lanceolata Trinius, 44, 53 

Perrierbambus A. Camus, 52 

Pharus P. Browne, 14, 28, 38, 40, 44, 53 

Pharus glaber Humboldt, Bonpland, and 

Phragrnites Adanson, 45 

Phyllostachys Siebold and Zuccarini, 15, 

Piresia Swallen, 21, 24, 28, 36, 44, 52, 53 

Piresia goeldii Swallen, 28, 44, 53 

Piresia sympodica (Doell) Swallen, 12 

Pleioblastus Nakai, 24, 52 

Poa L., 45 

Pseudocoix A. Camus, 52 

Pseudosasa Makino, 15, 24, 52 

Pseudostachyum Munro, 52 

PiLelia Franchet, 21, 37, 52 

and Kunth, 21 

Chase, 44, 53 

21, 28, 36, 53 

and Kunth, 28 

45, 52 

Kunth, 21, 44, 53 

28, 37, 38, 52 

Racemobanibos Holttum, 52 

Raddia Bertoloni, 28, 36, 52 

Raddia brasiliensis Bertoloni, 44, 53 
NUMBER 11 

Raddia costaricensis Hitchcock, 14, 28, 

Raddia guianensis (Brongniart) HitchRaddiella Swallen, 36, 52 

Raddiella nana (Doell) Swallen, 44, 53 

Reederochloa Soderstrom and Decker, 45 

Reitzia Swallen, 24, 28, 36, 52 

Reitzia smithii Swallen, 36, 44, 53 

Rettbergia Raddi, 52 

Rhynchoryza Baillon, 37 

Saccharurn oficinarum L., 40 

Sasa Makino and Shibata, 15, 24, 52 

Sasaella Makino, 52 

Sasamorpha Nakai, 52 

Schizostachyum C. G. D. Nees, 15, 21, 52 

Schizostachyum acutiporum Munro, 12 

44, 53 

cock, 14 

Semiarundinaria Makino ex Nakai, 52 

Shibataea Makino ex Nakai, 52 

Sinarundinaria Nakai, 28, 52 

Sinarundinaria murielae (Gamble), NaSinobambusa Makino ex Nakai, 24, 52 

Sinocalamus McClure, 52 

Sorghum bicolor (L.) Moench, 40 

Spinifex L., 45 

Stipa L., 20, 38 

Strephium guianense Brongniart [ZRadStreptochaeta Schrader ex C. G. D. Nees, 

Streptochaeta sodiroana Hackel, 44, 53 

Streptogyna Palisot de Beauvois, 28, 45, 

kai, 37 

dia guianensis] 

36, 38, 40, 44, 45, 52 

52 

Teinostachyum Munro, 52 

Teinostachyum attenuatum Munro, 44, 

Thamnocalamus Munro, 52 

Thyrsostachys Gamble, 28, 52 

Triticum L., 42 

Triticum aestiuum L., 40, 42 

53 

Uniola L., 38 

Yushania K. H. Keng, 52 

Zea L., 45 

Zea mays L., 40 

Zeugites P. Brown, 45 

Zizania L., 45 

Zizania Zatifolia (Grisebach) Stapf, 13 

U. 0. GOVERNMENT PRINTING OFFICE1 1873-484-323/44