A REVISION OF RADDIELLA
(POACEAE: BAMBUSOIDEAE:
OLYREAE)'
Fernando O. Zuloaga2
and Emmet J. Judziewicz3
ABSTRACT
Raddiella is a genus of seven species of low- to mid-elevation, small herbaceous bamboos (Poaceae: Bambusoideae:
Olyreae) that occurs from Panama and Trinidad to Bolivia and Brazil. Raddiella esenbeckii is widespread in savannas
and cerrados, but its six congeners are rare, and many occur only on wet rocks in the spray zone below waterfalls.
The new Brazilian species, R. minima, with the smallest leaves of any bambusoid grass, and R. lunata, with lunate
female florets, are described. This first revision of Raddiella includes a key to the recognized species, descriptions,
and distribution maps, as well as scanning electron micrographs of the female florets, which reveal taxonomically
important interspecific differences.
Along with the Cuban genus Mniochloa Chase,
members of Raddiella Swallen (Poaceae: Bam-
busoideae: Olyreae) are the smallest bambusoid
grasses in the world. The genus was described
(Swallen, 1948) on the basis of three species, Rad-
diella nana (Doell) Swallen (= R. esenbeckii (Steu-
del) Calder�n & Soderstrom), the type species; R.
truncata Swallen (= Parodiolyra lateralis (Nees)
Soderstrom & Zuloaga); and R. malmeana (E.
Ekman) Swallen. Swallen characterized the genus
as monoecious with the maile and female spikelets
in different inflorescences; the pedicels of female
spikelets not conspicuously thickened upwards; fe-
male spikelets with the glumes 3-nerved, and the
floret indurate, white, and smooth.
Soderstrom (1965) described three new species
of Raddiella, R. kaieteurana, R. maipuriensis,
and R. potaroensis, and included a key to the six
species in the genus. Later, based on priority, Cal-
der6n & Soderstrom (1980) considered R. esen-
beckii as the valid name for the type species of
the genus and transferred Panicum molliculmum
Swallen to Raddiella (as R. molliculma).
Examination of more herbarium material since
Soderstrom's summary of the genus has revealed
two distinctive new species of Raddiella, and a
scanning electron microscope study of female flo-
rets has proven useful in clarifying species limits,
warranting the following revision of the genus.
MATERIAL AND METHODS
Classical alpha taxonomic methods were used to
study Raddiella. In addition, scanning electron
micrographs were made of the female florets of a
few populations of each of the species except R.
minima, using the same procedures and equipment
as described by Soderstrom & Zuloaga (1989).
The vouchers for this study are marked with an
asterisk (*) in the lists of specimens examined in
the taxonomic treatment.
MORPHOLOGY
Species of Raddiella are remarkable in the
Bambusoideae for their very small size. Most spe-
cies appear to be annuals and represent the only
annual bambusoids, excluding oryzoids. Many are
obligate phreatophytes, growing only on wet rocks
in the constantly moist spray zone of riversides
below waterfalls; exceptions are the perennials R.
esenbeckii and possibly R. minima, which often
grow in dry savannas and cerrados. Raddiella
esenbeckii and possibly R. minima are also unique
in the genus in exhibiting nyctinasty, or sleep move-
ments, the blades folding upwards at night or under
water stress. The blades are firm and conspicuously
asymmetrical in R. esenbeckii and R. minima,
thinly membranous and only slightly asymmetrical
in the other species.
' We are grateful to Vladimiro Dud�s and Bruno Manara for the illustrations, to Bruno Manara for assistance with
the Latin diagnoses, and to Gerrit Davidse, Lynn Clark, Edgardo Romero, Mary Sangrey, and the late Thomas R.
Soderstrom for help in various ways. The first author expresses gratitude to the Guggenheim Foundation for a fellowship
that allowed him to work on this research at the Missouri Botanical Garden. Figure 13A-G is used with permission
of Paul E. Berry, editor of the Flora of the Venezuelan Guayana.
2 Instituto de Botinica Darwinion, Casilla de Correo 22, 1642 San Isidro, Argentina.
' Department of Botany, Birge Hall, University of Wisconsin, Madison, Wisconsin 53706, U.S.A.
ANN. MISSOURI BOT. GARD. 78: 928-941. 1991.


Volume 78, Number 4
1991
Zuloaga & Judziewicz
Revision of Raddiella
Species of Raddiella bear terminal and nu-
merous axillary inflorescences; both types are con-
tracted, few-flowered, and barely exserted from the
leaf sheaths. The several inflorescences arising from
the uppermost node each consist of several (rarely
one as in R. minima) early-deciduous maile spike-
lets on short, filiform pedicels. Several axillary in-
florescences occur at each node, and the disposition
of spikelets in these is more variable. Typically,
the entire inflorescence is female, with spikelets
borne on short, filiform pedicels. However, at a
given node, inflorescences bearing 1-2 terminal
female spikelets as well as 1-several short-pedi-
celled maile spikelets positioned below them can be
found. Exceptions to these patterns include R.
molliculma, in which both terminal and axillary
inflorescences are long-peduncled and each consists
of 1-2 terminal maile and 1-2 subterminal female
spikelets; and R. lunata, with racemose-appearing
inflorescences that may be up to 12-flowered, but
in which the disposition of the sexes in the single,
overly mature specimen is not entirely clear.
The spikelets of Raddiella are fairly typical of
those of other olyroid genera. In the female spike-
lets, the glumes vary from persistent in R. esen-
beckii and R. minima, to deciduous together with
the floret in the other species. The glumes are 3-
5-nerved, and there is a characteristic indurate,
thickened, interglumal internode present. The fe-
male floret morphology is ellipsoidal in ail species
(Fig. 13) except for R. lunata, which has curious,
lunate (crescent-shaped in profile) florets that taper
to an acute point at both ends (Fig. 14). Floret
epidermal texture, however, ranges from smooth
to strongly papillose and is discussed in the section
on anatomy below.
The male spikelets are hyaline and early decid-
uous, and their relative size with respect to the
female spikelets is apparently of some taxonomic
value.
The caryops.es of most species are ovoid-ellip-
soid, and the h)Jum is central punctiform or short-
elliptical, a type not present in other bambusoid
grasses (CalderSn & Soderstrom, 1980). However,
in R. esenbeckii (but not its putative sister species
R. minima) the hilum is short-linear.
ANATOMY
A scanning electron microscope study of the
mature female florets proved useful in clarifying
species limits in Raddiella, just as in Panicum
(Zuloaga, 1987) and Olyra (Soderstrom & Zuloa-
ga, 1989). Most species of Raddiella had distinc-
tive lemmatal epidermal features that are described
below. Common to ail species was the presence
near the base and/or apex of the palea of circular
excavations, 10-15 �m diam., similar to those
present on the female paleas of various species of
Olyra L. and Parodiolyra Soderstrom & Zuloaga
(Soderstrom & Zuloaga, 1989). These excavations
are apparently caused by the deflation of certain
cells when placed in the vacuum of the scanning
electron microscope.
Raddiella esenbeckii (Figs. 1, 2). Female lem-
ma completely smooth.
Raddiella kaieteurana (Figs. 3, 4). Both lemma
and palea covered throughout with simple papillae
4-5 tm diam.
Raddiella lunata (Figs. 9, 10). Both lemma
and palea with cells with a single large, central,
compound papilla 9-11 �m diam., bearing on its
raised margins 3-5 smaller papillae 3-4 pm diam.
Raddiella malmeana (not illustrated). Lemma
completely smooth (but available floret slightly im-
mature).
Raddiella minima. Not included in scanning
electron microscope study; in an optical micro-
scope, the lemma appears to be completely smooth,
as in R. esenbeckii.
Raddiella molliculma (Figs. 5, 6). Both lemma
and palea with the central portion of each cell
enlarged and protruding (ca. 30 x 20 pm), and
with 10-12 papillae, 3-5 tm diam., present along
the undulating margins.
Raddiella potaroensis (Figs. 7, 8). Both lemma
and palea with cells with the central portion of each
cell enlarged, 15-18 pm diam., surmounted by 7-
10 smaller papillae 3-4 �tm diam.
RELATIONSHIPS
The possible affinities of Raddiella with several
other putatively related genera of the Olyreae are
summarized in Table 1. It will be noted that the
type species, R. esenbeckii, has several characters
in common with Parodiolyra lateralis (Nees) So-
derstrom & Zuloaga rather than with the phreato-
phytic species of Raddiella (with the possible ex-
ception of the poorly known R. minima): perennial
habit; firmly membranous leaves; smooth female
florets; and a short-linear rather than punctiform
hilum. Arguing for the retention of the phreatophy-
tic species within Raddiella is the presence of the
following feature in common between them and R.
esenbeckii: few-flowered panicles with the sexes
usually separate, the males terminal and females
axillary. Moreover, R. esenbeckii and P. lateralis
have quite different chromosome numbers (n = 10
and 18 (Davidse & Pohl, 1978), respectively), and
929

Annals of the
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FIGURES 1-6. Scanning electron micrographs of female florets of Raddiella species.-1, 2. R. esenbeckii (Pires
51123).-3. R. kaieteurana (Egler 1244).-4. R. kaieteurana (Maguire & Fanshawe 23089).-5, 6. R. mol-
liculma (Guti�rrez & Schultes 616). Scale bar 50 tm for 1, 3, 5; 10 �m for 2, 4, 6.
the latter has leaf blades that are not nyctinastic
and female spikelets with indurate, strongly clasp-
ing glumes that become black at maturity.
Raddiella Swallen in Maguire et al., Bull. Torrey
Bot. Club 75: 89. 1948. TYPE: Raddiella
nana (Doell) Swallen [= R. esenbeckii (Steu-
del) Calder�n & Soderstrom], Smithsonian
Contr. Bot. 44: 21. 1980.
TAXONOMIC TREATMENT Plants small, monoecious, either tufted peren-
Asterisks (*) indicate vouchers used in this study. niais or delicate annuals, often forming low mats.
930

Volume 78, NuLmber 4
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Zuloaga & Judziewicz
Revision of Raddiella
FIGURES 7-10. Scanning electron micrographs of female florets of species of Raddiella.-7, 8. R. potaroensis
(Maguire & Fanshawe 32277).-9, 10. R. lunata (Rondon s.n.). Scale bar 50 ,m for 7, 9; 10 �m for 8, 10.
Leaves small, pseudopetiolate; blades elliptical to
ovate-triangular, often strongly asymmetrical and
with an apiculate apex, exhibiting sleep movements
or not. Inflorescences small, few-flowered, 1-sev-
eral from both terminal and axillary nodes, barely
exserted from the leaf sheaths, 2-6(-12) spikelets
per inflorescence. Terminal inflorescences maile and
female or more commonly strictly maile, rarely
strictly female; axillary inflorescences either ail fe-
male or with female and maile spikelets; female
spikelets minutely cupulate at apices. Spikelets
1 -flowered, the broad female spikelets shorter than
to as long as the narrow maile spikelets. Female
spikelets falling entire from pedicels or in one spe-
cies the glumes persistent and the floret falling,
ovate-lanceolate; glumes subequal, membranous,
as long as the spikelet, acute, 3-5-nerved, the
lateral nerves often obscure; floret elliptical to ovoid,
acute, glabrous, thinly coriaceous, stramineous or
becoming dark when mature, the margins of the
lemma inrolled over the edges of the palea; style
1, stigmas 2. Caryopsis ovoid to globose, brownish
tan; embryo small, basal; hilum punctiform or short-
linear. Maile spikelets borne on filiform pedicels,
hyaline, glabrous, early deciduous, linear to lan-
ceolate; glumes absent; lemma 3-nerved; palea
2-nerved; stamens 3.
Distribution and ecology. Seven species
ranging from Panama and Trinidad to Bolivia and
Brazil (to S�o Paulo); savannas, forest margins, or
among wet rocks near rivers and waterfalls, from
near sea level to 1,500 m.
Raddiella has two centers of diversity: (1) the
Guayana Highlands, with four species, two of them
endemic (including the Colombian species R. mol-
liculma at the far western edge of the Guayana
Highlands formation); and (2) the western Brazilian
Planalto from Rond�nia to northern Mato Grosso
and southern Pari, with five species including three
endemics. More new species may be expected from
both areas.
KEY TO THE SPECIES OF RADDIELLA
la. Female florets smooth 2..... .... ... ......... 2
2a. Leaf blades elliptical, + symmetrical, acute
at both base and apex; female glumes de-
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932
Annals of the
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TABLE 1. Comparison of Raddiella with related genera.
Raddiella
Parodiolyra Parodiolyra Raddiella (phreatophytic
Olyra lateralis (2 species) esenbeckii species)
Habit Caespitose Caespitose to Sprawling Caespitose Sprawling
perennials sprawling perennials perennials annuals
perennials
Nyctinasty - - + -?
Leaf blade asymmetry - (+) + - + -
Leaf blade texture Firm Firm Firm Firm Delicate
Axillary inflore-
scences well - -, + -, + + +
developed
Inflorescence size Large Moderate Moderate Small Small
Sexes in separate - (+) - - + +
inflorescences
Female spikelet c (f) f f f f
pedicels clavate or
filiform
Female spikelet falling - (+) + + - +
entire
Female spikelet: - + + + +
thickened internode
between glumes
Female floret Variable Smooth Smooth, viscid Smooth Papillose or
texture smooth
Hilum Fully linear Short-linear Short-linear Short-linear Punctiform
(1/2 to 3/4 (ca. 1/2 length) (ca. 1/2 length)
length)
Chromosome n= 7, 10, 11, 18 Unknown 10 Unknown
20, 22
ciduous along with the floret ..................................
4. R. malmeana
2b. Leaf blades ovate-triangular, asymmetri-
cal, the base truncate, the apex acute or
apiculate; female glumes persistent, only
the floret deciduous .................................. ......................... 3
3a. Female spikelets 1.9-2.7 mm long;
male spikelets 3-5 mm long, (1-)2-
4 per inflorescence; leaf blades 9-22
mm long, 4-11 mm wide; caryopsis
with the hilum short-linear; wide-
spread ..... ... 1. R. esenbeckii
3b. Female spikelets 1-1.4 mm long; male
spikelets ca. 1.3 mm long, 1 per in-
florescence; leaf blades 4-6 mm long,
2.7-3.3 mm wide; caryopsis with the
hilum punctiform; rare, Parai, Brazil
5. R. minima
lb. Female florets minutely papillose with simple or
compound papillae ail over surface ... ............ 4
4a. Female florets lunate (crescent-shaped) in
profile, dorsally compressed, abruptly
beaked; female floret epidermis with a sin-
gle compound papilla in the middle of each
cell; rare, Rond�nia, Brazil .......... 3. R. lunata
4b. Female florets straight and lanceolate in
profile, terete, not beaked; female floret
epidermis without a compound papilla in
the m iddle of each cell . .................. ............. 5
5a. Inflorescences long-exserted, some pe-
duncles at least 5 cm long; female
florets with papillae along the cell mar-
gins; rare, Caqueta, Colombia ...............
............................................................. 6 . R . m olliculm a
5b. Inflorescences with bases included in
leaf sheaths, or short-exserted on pe-
duncles less than 1 cm long; female
florets with 1-several papillae per cell;
Venezuela, Guianas, Brazil ............................ 6
6a. Leaf blades with the lower sur-
face hispid to strigose through-
out; female spikelets 1.4-2 mm
long; female floret epidermis with
1 simple papilla per cell; male
spikelets 4-5.8 mm long .........
....................... ................... 2. R . kaieteurana
6b. Leaf blades with the lower sur-
face glabrous or with short, scab-
rid hairs only on the veins; female
spikelets 1.3-2.3 mm long; fe-
male floret epidermis with 7-10
simple papillae per cell; male
spikelets 2.7-4.2 mm long ............
... ................. .................. 7. R . p otaroensis


Volume 78, Number 4
1991
Zuloaga & Judziewicz
Revision of Raddiella
1. Raddiella esenbeckii (Steudel) Calder�n &
Soderstrom, Smithsonian Contr. Bot. 44: 21.
1980. Panicum esenbeckii Steudel, Syn. PI.
Glumac. 1: 90. 1854; based on Panicum lat-
erale var. 3 Nees, Agrost. Brasil. 213. 1829.
Basis in part of Olyra nana Doell in C. Mar-
tius, FI. Bras. 2(2): 329. 1877, nom. superfl.
Raddia nana (Doell) Chase, Proc. Biol. Soc.
Wash. 21: 185. 1908. Raddiella nana (Doell)
Swallen, Bull. Torrey Bot. Club 75: 89. 1948.
TYPE: Brazil. Amazonas: Rio Negro, Ega, Mar.
tius s.n. (holotype, M? not seen; the same
specimen designated as a lectotype of O. nana
M?, not seen). Figures 1, 2, 13A-D.
Densely tufted perennials, with up to 60 un-
branched culms per clump. Culms sprawling, de-
cumbent to geniculate, the erect portions 8-40 cm
tall, wiry; internodes cylindrical, glabrous to sparse-
ly pilose with short, retrorse hairs; nodes thickened,
densely pilose with whitish retrorse hairs. Leaves
in complements of 7-15, nyctinastic, the blades
folding upwards at night or under water stress;
sheaths striate, glabrous to short-pilose, densely so
toward the summit, one margin membranous, the
other short-ciliate, short-auricled, the auricle mem-
branous on one side; ligules ca. 0.3 mm long,
membranous, apically short-ciliate; pseudopetioles
ca. 0.5 cm long, densely pilose; blades 9-22 mm
long, 4-11 mm wide, ovate-triangular, asymmet-
rical, truncate at the base, acute and short-apic-
ulate at the apex, flat, firmly membranous, either
glabrous, or short-pilose near the base on the upper
surface, to densely puberulent on both surfaces,
the lower margins ciliate, the lower surface purplish
in some specimens. Inflorescences terminal and
axillary; terminal inflorescences 3-5, with male
spikelets only, on cylindrical, glabrous peduncles
1-2 cm long, each inflorescence with (1 -)2-4 male
spikelets on short, glabrous pedicels; axillary inflo-
rescences both female and male, the female inflo-
rescences on short-pilose peduncles 5-8 mm long,
each bearing 2 short-pedicelled female spikelets.
Female spikelets 1.9-2.7 mm long, 0.7-0.9 mm
wide, ovoid; glumes firmly membranous, greenish
becoming blackish, sparsely to densely short-pilose
with spreading hairs, 3-nerved, persistent, the in-
ternode between the glumes thickened, the lower
glume acute, slightly shorter than the acuminate
upper glume; floret 1.6-2 mm long, ellipsoid, co-
riaceous, smooth, shiny, glabrous, whitish becom-
ing dark, deciduous. Caryopsis 1-1.2 mm long,
0.7-0.8 mm wide, long-ellipsoid, dorsally com-
pressed; hilum short-linear, ca. VI the length of the
caryopsis, extending from near the center to near
the base; embryo ca. '/ the length of the caryopsis.
Male spikelets borne on minutely cupuliform pedi-
cels, 3-5 mm long, ca. 1 mm wide, lanceolate,
acuminate, greenish to purplish, hyaline, glabrous
to sparsely hispid with short hairs; glumes occa-
sionally present, to 3.7 mm long, linear-lanceolate,
sparsely hispid; lemma as long as spikelet, lanceo-
late, acuminate, glabrous to sparsely hispid with
short hairs; stamens with anthers 1.3-3 mm long.
Distribution and ecology. Panama and
northern South America (including Trinidad) to
Bolivia and central Brazil (Fig. 11); from 0 to 1,500
m in semishaded or more often dryish, open places:
gallery forests, woodlands, savannas, and cerrados,
often on rocky or sandy soil.
Chromosome number. n = 10 (Davidse &
Pohl, 1972).
Representative specimens examined. PANAMA. PAN-
AMA: 7 mi. N of Cerro Azul, 2,600 ft., 13 Nov. 1965,
Blum et al. 1789 (MO); Cerro Campana, 900 m, 21
Jan. 1984, van der Werff& Herrera 6156 (MO); hills
NE of Hacienda La Joya, 50-300 m, 9 Dec. 1934, Dodge
et al. 16882 (MO). HERRERA: N slope of Cerro Alto Higo,
2,400 ft., 5 Aug. 1978, Hammel 4202 (MO). COLOMBIA.
AMAZONAS: Bella Vista, Rio Igar�-Paran�, 8 Sep. 1973,
Sastre 2152 (US). META: La Macarena, Rio Guayabero,
Sabanas de Arenisca, Jan.-Mar. 1959, Garcia-Barriga
& Jaramillo 17089 (US). VAUP�S: Rio Guainia, Cafio del
Caribe, between Isla del Venado and San Jos�, 2�45'N,
67�50'W, 2 Nov. 1952, Schultes et al. 18262 (US); Rio
Guainia basin, Rio Naquieni, vicinity of Cerro Monachi,
June 1948, Schultes & L�pez 10115 (US); Rio Kan-
anari, Cerro Isibukuri, 28 Oct. 1951, Schultes & Cabrera
14452 (US). VENEZUELA. AMAZONAS: Piedra Arauicaua,
Rio Yatua, 27 Sep. 1957, Maguire et al. 41608 (US),
15 July 1959, Wurdack & Adderley 43457 (US); Rio
Cunucunuma, occasional on moss-covered boulders, up-
river from Playa Alto, 14 Nov. 1950, Maguire et al.
29500 (US); banks of Rio Cuao, above Cuao Creek, 25
Nov. 1948, Maguire & Politi 27376 (US); Rio Atacavi,
ca. 1 km above the confluence with Rio Atabapo, 6-19
July 1969, Bunting et al. 3658 (US); Cerro Duida, Rio
Cunucunuma, Culebra Creek, 1,500-1,600 m, 21 Nov.
1950, Maguire et al. 29629 (US). ANZO�TEGUI: Fila El
Purgatorio, S of El Zamuro, 10�02'N, 64�17'W, 1,100
m, 24 Nov. 1981, Davidse & Gonzdlez 19335 (MO).
BOLIVAR: cercanias del campamento en el lado sur del Rio
Ich�n, tributario del Rio Paragua, debajo del Salto Maria
Espuma, 4�46'N, 63�18'W, 30 Dec. 1961, Steyermark
90470 (US); Dist. Heres, San Salvador de Pa�l, 6�02'N,
62�53'W, 2 Dec. 1982, Davidse & Huber 23128 (US).
SUCRE: 8 km S de Santa F�, 10�16'N, 64�24'W, 230 m,
Davidse & Gonzdlez 19069 (MO, US); carretera Guanta-
Los Altos, Tamayo 2146 (US). T�CHIRA: Dist. Uribante,
Siberia to Pregonero, 8�55'N, 71�40'W, 1,300 m, 11
July 1983, van der Werff& Gonzdlez 5365 (MO). TRINI-
DAD. Aripo Savanna along the Cumuto road, 3 Nov. 1929,
Broadway 7685 (MO), 5 Aug. 1970, Davidse 2550
(MO, US). GUYANA. Kaieteur savanna, 5 Sep. 1937,
Sandwith 1375 (US), 11 Feb. 1962, Cowan & Soder-
strom 1807 (US); Waranama ranch, Harrison & Per-
saud 1069 (BRG, K); Lama Dam, Jenman 5971 (BRG).
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Annals of the
Missouri Botanical Garden
FIGURE 11. Distribution of Raddiella esenbeckii.
SURINAM. Brinckhill Nature Reserve, 14 Dec. 1967,
Wildschut & Teunissen 11346 (US); Moengo tapoe ad
Grote Zwiebelzwamp, Lanjouw & Lindeman 872 (NY,
U); Sipaliwini savanna, Oldenburger et al. 141 (U). FRENCH
GUIANA. Passoura, 3 Apr. 1958, Hoock 942 (CAY);
Savane des Singes, 5�05'N, 52�42'W, Cremers & Hoff
10680(CAY, US). BRAZIL. AMAP�: Matapi, Pires & Silva
4797 (US); Igarap� do Paia, km 110 on road to Amap�,
20 July 1962, Pires & Cavalcante 52233 (MO, NY,
US). AMAZONAS: 3 km E of Borba near the Rio Madeira,
4�23'S, 59�35'W, 22 June 1983, Hill 12753 (F, MO,
US); Rio Jauari, affluent of Rio Arac�, 0�49'N, 63�20'W,
July 1985, Huber et al. 10710 (MO); Rio Urub�, Serra
da Lua, 6 June 1968, Prance et al. 5005 (MO); Manaus,
Rio Cuieiras, Igarap� Cachoeira, 19 Dec. 1961, Ro-
drigues & Wilson 3191 (US); km 38 on road from
Humait� to P�rto Velho, 6 May 1982, Teixeira et al.
260 (MO). BAHIA: Serra do Sincor�, 16 km N of Barra
da Estiva on the Paragua�� road, 13�20'S, 41�20'W, 31
Jan. 1974, Harley et al. 15746 (US); 2-5 km N of
Len�ois, 11 June 1981, Mori & Boom 14339 (MO).
DISTRITO FEDERAL: Bacia do Rio Bartolomeu, 5 May 1980,
Heringer et al. 4626 (US); Chapada da Contagem, Par-
que Municipal do Gama, ca. 25 km W of Brasilia, 1,100
m, 3 Feb. 1968, Irwin et al. 19474 (US); 700-1,000
m, 31 Aug. 1964, Irwin & Soderstrom 5801 (US). c;Ols:
ca. 10 km S of Alto do Paraiso, 22 Mar. 1969, Irwin
et al. 24921 (MO, US); S Serra Dourada, gallery forest
20 km E of Formosa, 13�45'S, 48�50'W, 18 May 1956,
Dawson 14956 (US); vicinity of Goiabeira, between An-
�polis and Goias, 23 Mar. 1930, Chase 11510 (MO, US);
ca. 3 km E of Alto Paraiso on road to Nova Roma, 7
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Volume 78, Number 4
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Zuloaga & Judziewicz
Revision of Raddiella
Mar. 1973, Anderson 6604 (MO, US). MARANHAO: Pedra
Caida, 35 km N of Carolina, 7�08'S, 47�25'W, 14 Apr.
1983, Taylor et al. E-1240 (US). MATO GROSSO: ca. 5
km N of Barra do Gar�as, S face of mountain, 7 May
1973, Anderson 9885 (US); km 762, Santar�m-Cuiab�
road, 9�35'S, 54'55'W, Amaral et al. 806 (F, MO).
MINAS GERAIS: Vaccaria, Serra do Cip�, Apr. 1925, Chase
9257 (MO, US); Metallurgica, Serra de Ouro Branco, 23
Dec. 1929, Chase 10290 (MO, US); Rio Jequiti, ca. 25
km E of Diamantina, 790 m, 21 Mar. 1970, Irwin et
al. 27993 (MO, US); Serra do Espinha�o, 3.5 km by
road SW of Rio Jequiti and Mendanha, 14 Apr. 1973,
Anderson 8922 (US). PARA: 7 km SE of Vigia, 0�55'S,
48�04'W, 31 Mar. 1980, Davidse et al. 17689 (MO);
Rio Aru�, Black 49-844 (US). ROND�NIA: Abun�, Rio
Madeira, 11 July 1968, Prance et al. 5887 (MO); P�rto
Velho, caminho para o km 8, 26 May 1952, Black &
Cordeiro 52-14526 (US). SAO PAULO: S�o Jos� dos Cam-
pos, 16 Dec. 1909, Lofgren 4680 (US). BOLIVIA. BENI:
Prov. Vaca Diez, 15 km W de Guayamerim, camino a
Riberalta, en campos con rocas aflorantes, 17 Apr. 1979,
Krapovickas & Schinini 35062 (US).
This species :is variable in stature. Alone among
members of the genus, the leaf blades exhibit sleep
movements, folding upwards at night or under wa-
ter stress.
The superficially similar Parodiolyra lateralis
differs in its sprawling habit, larger, more rigid
blades lacking sleep movements, and larger, more
open mixed panicles with mature female spikelets
with blackish, indurate, 3-7-nerved glumes that
strongly invest the floret.
2. Raddiella kaieteurana Soderstrom, Mem.
New York Bot. Gard. 12(3): 6. 1965. TYPE.
Guyana: Kaieteur Plateau, on moist cliff faces
along trail from Kaieteur Plateau to Tukeit,
1,100 ft., 4 Feb. 1962, R.S. Cowan & T.R.
Soderstrom 1742. (holotype, US*; isotypes,
GH, K, NY, P). Figures 3, 4, 13E-G.
Delicate mat-forming herbs of indefinite dura-
tion. Culms weak, decumbent, rooting and branch-
ing at the lower nodes, the flowering portion 5(-
20) cm long, many-noded; internodes compressed,
glabrous. Leaves with the sheaths striate, longer
than the internodes, greenish to purplish, with long
hairs near the apex, otherwise sparsely pilose to
glabrescent; ligules membranous, 0.3-0.5 mm long;
pseudopetioles 0.5 mm long, hirtellous; blades 8-
17 mm long, 3-8 mm wide, flat, delicately mem-
branous, densely hispid to strigose on both surfaces
with long and short hairs, the base slightly asym-
metrical, obtuse, and subcordate, the apex acute
and slightly apiculate, the margins ciliate through-
out or only toward the base of the blade. Inflores-
cences terminal and axillary from the upper nodes,
with bases included in leaf sheaths or short-exserted
on peduncles less than 1 cm long; terminal inflo-
rescences 2-6, mostly male, each bearing 1-2
spikelets, or occasionally female spikelets present;
axillary inflorescences female, exserted up to 3 mm
on filiform peduncles and bearing 1-3 female spike-
lets on divergent pedicels 1.5-5 mm long. Female
spikelets 1.4-2 mm long, 0.6-0.8 mm wide, ellip-
soid, falling entire; glumes ovate-elliptical,
acuminate, subequal, prominently nerved, sparsely
short-pilose with spreading hairs to uncommonly
glabrous, greenish, the lower glume 3-nerved, sep-
arated from the 3-5-nerved upper glume by a short
internode; floret 0.8-1.7 mm long, 0.5-0.6 mm
wide, narrowly ellipsoid, dorsally compressed, mi-
nutely papillose, whitish becoming brownish at ma-
turity; lemma evidently 3-5-nerved. Caryopsis 0.6-
0.8 mm long, 0.4-0.7 mm wide, broadly ellipsoid;
hilum oblong, placed in the middle of the caryopsis
and extending slightly toward the base; embryo %'
or less the length of the caryopsis. Male spikelets
borne on pedicels 0.5-2.3 mm long, 4-5.8 mm
long, 0.6-0.8 mm wide, fusiform, hyaline, sparsely
short-pilose toward the apex; glumes occasionally
present, to 4 mm long, linear-lanceolate; lemma
3-5-nerved; stamens with anthers 2-2.8 mm long.
Distribution and ecology. Venezuela (Boli-
var), Guyana, Surinam, and northern Brazil (Pari);
on damp cliff faces or in the spray of waterfalls,
from 100 to 810 m (Fig. 12).
Additional specimens examined. VENEZUELA.
BOLIVAR: Dist. Piar, Amaruay-tepui, S side about 1 km
from SW corner of tepui, 5�54'N, 62�15'W, 550-810
m, 26 Apr. 1986, Liesner & Holst 20369(MO). GUYANA:
semishaded rock face in forest along trail from Kaieteur
Falls to Tukeit, about 1 km E of the airstrip, 300 m,
Cowan & Soderstrom 2027 (K, NY, US); 29 Apr. 1944,
Maguire & Fanshawe 23087 (MO, NA, NY, US*); 24
Feb. 1962, Cowan & Soderstrom 1918(US); Apr. 1988,
Hahn et al. 4163 (BRG, US); anno 1881, Jenman 1277
(US). SURINAM.: Tafelberg, base of N escarpment, under
drips, 390 m, 11 Aug. 1944, Maguire 24327 (MO, NA,
NY, U); NW side, Geyskes 998 (U). BRAZIL. PARA: Rio
Cururur (affluent of Rio Tapajos), Cachoeira Kereputi�, in
a hole on sandstone rocks, 3 Mar. 1960, Egler 1244
(US*).
As presently conceived, this species is variable.
In Egler 1244 the female spikelets are only 0.9-
1 mm long and the glumes are covered with short
hairs, but scanning electron micrographs revealed
that female floret texture is similar to that of typical
R. kaieteurana. An unusual feature of Cowan &
Soderstrom 1918 is the presence of terminal fe-
male inflorescences with two spikelets. Liesner &
Holst 20369 differs from typical R. kaieteurana
in its short-pilose to glabrous leaf blades and com-
pletely glabrous female glumes.
935

Annals of the
Missouri Botanical Garden
FIGURE 12. Distribution of Raddiella kaieteurana, R. lunata, R. malmeana, R. minima, R. molliculma, and
R. potaroensis.
3. Raddiella lunata Zuloaga & Judziewicz, sp.
nov. TYPE. Brazil. Rond�nia: Serr-i dos Pacaas
Novos, Cab. do Caut�rio, planta umbrophila,
na entrada das lapas, firmas, predas, etc., Mar.
1917, C. Rond�n s.n. [as J.G. Kuhlmann
1863] (holotype, RB; isotypes, K, MO, NY,
SI, SP, US*). Figures 9, 10, 14.
Ab omnibus conspecificis differt: spicula, flosculo et
caryopside lunatis abrupte rostratis, necnon flosculo pa-
pilla composita in medio cuiusque cellulae praedito.
Delicate, sprawling, mat-forming annuals. Culms
decumbent, rooting and branching at the lower
nodes, the erect portions 7-15 cm tall, many-
noded, unbranched; internodes cylindrical, hollow,
glabrous; nodes thickened, with short, retrorse,
whitish hairs. Leaves with the sheaths striate, gla-
brous, slightly inflated, the margins membranous,
the auricles membranous, glabrous, the summit
truncate; ligules not noted; pseudopetioles ca. 0.1
mm long, brownish, short-pilose; blades 10-15 mm
long, 2.5-3.5 mm wide, lanceolate, delicately
936

Volume 78, Number 4
1991
Zuloaga & Judziewicz
Revision of Raddiella
H I l
1 mn
1 cm
1 mm c
B C
F G
1 mm
FIGURE 13. A-D. Raddiella esenbeckii (Huber 2126).-A. Habit.-B. Female spikelet.-C. Female floret.-D.
Male spikelet. E-G. Raddiella kaieteurana (Liesner 20414).-E. Habit.-F. Female spikelet.-G. Female floret.
H, I. Raddiella molliculma (Grassl 10024).-H. Female spikelet, dorsal view.-I. Female spikelet, ventral view.
J-L. Raddiella potaroensis (Cowan & Soderstrom 2162).-J. Female spikelet, dorsal view.-K. Female spikelet,
ventral view. - L. Female floret.
membranous, glabrous to sparingly short-pilose on
both surfaces (especially on the veins below), the
base slightly asymmetrical, acute at the apex, the
margins scabrous. Inflorescences both terminal and
axillary, with 1--several inflorescences produced at
each node, short-exserted on glabrous, filiform pe-
duncles up to 10 mm long; individual inflorescence
a contracted, racemelike panicle 5-10 mm long,
the rachis slightly sinuous, glabrous, alternately
bearing 2-12 spikelets on short pedicels 0.5-1.5
mm long, or occasionally with a lower branch up
to 3 mm long bearing 2 spikelets; terminal spikelet
female, the lateral ones maile or occasionally a few
females. Female spikelets ca. 1 mm long, obovoid,
lunate in profile, falling entire; glumes delicately
membranous, short-hispid, 3-nerved, the lower
glume not covering the apex of the floret, the upper
glume as long as the floret, flat; floret 0.8-1 mm
long, 0.5-0.6 mm wide, obovoid, dorsally com-
pressed, concave on the ventral side, convex on
the dorsal side, acute at the base, rather abruptly
beaked at the apex, coriaceous, whitish becoming
brown at maturity, strongly papillate; lemma con-
spicuously grooved on the dorsal surface, slightly
winged, the margins covering the edges of the palea
with wide margins. Caryopsis 0.6-0.8 mm long,
0.5-0.6 mm wide, ovoid, lunate, of the same gen-
eral morphology as the floret, slightly winged; hilum
937

Annals of the
Missouri Botanical Garden
A \1cm:
1R'
' D
1 mm
mmni
4 4
i linl
FIGURE 14. Raddiella lunata (Rondon s.n.).-A. Habit.-B. Detail of a node.-C. Leaf.-D. Inflorescence.-
E. Maile spikelet. F-J. Female spikelet.-F. Lower glume.-G. Upper glume. H-J. Floret.-H. Dorsal view.-I.
Ventral view.-J. Lateral view. K, L. Caryopsis.-K. Dorsal view.-L. Ventral view.
rounded at the middle portion of the caryopsis;
embryo 42 the length of the caryopsis. Maile spike-
lets 1.7-2.7 mm long, lanceolate-elliptical, acute,
hyaline, glabrous; lemma 3-nerved; stamen with
anthers 1-1.5 mm long.
Distribution and ecology. Known only from
the type collection made in the Serra dos Pac�as
Novos in Rond�nia, Brazil (Fig. 12).
This species differs from ail other congeners in
its lunate (crescent-shaped, hence the specific ep-
ithet) female floret that tapers rather abruptly to
both ends, and the surface of the floret, which has
a single compound papilla on each cell. The form
of the female spikelets could be associated with
dispersion by water.
In the mature plants at hand, the culms disar-
ticulate readily at the nodes. Whether this repre-
sents an adaptation for dispersai or is merely in-
dicative of senescence is unclear.
4. Raddiella malmeana (E. Ekman) Swallen,
Bull. Torrey Bot. Club 75: 89. 1948. Olyra
malmeana E. Ekman, Ark. Bot. 10(17): 21.
1911. Raddia malmeana (E. Ekman) A.
938
m1
1 mn
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Volume 78, Number 4
1991
Zuloaga & Judziewicz
Revision of Raddiella
Hitchc., Contr. U.S. Natl. Herb. 22: 505.
1922. TYPE. Brazil. Mato Grosso: Santa Ana
da Chapada, Buriti, in proruptis rupis ad ca-
taractam junta cum Sphagni, 16 June 1894,
Malme (Regnell Expedition I) 1684 (ho-
lotype, S n.v.; isotype, US*).
Annuals. Culms decumbent and rooting at the
lower nodes, the erect portions to 20 cm tall (ac-
cording to original description), many-noded, un-
branched; internodes glabrous. Leaves with the
sheaths longer than the internodes, striate, gla-
brous, the margins membranous, the auricles mem-
branous; ligules ca. 0.3 mm long, membranous;
pseudopetioles ca. 0.5 mm long, narrow, brownish,
glabrous; blades 5-10 mm long, 2-4 mm wide,
elliptical, delicately membranous, flat, sparingly
short-pilose on both surfaces or with scabrid hairs
on the veins only on the lower surface, � sym-
metrical, acute at both base and apex, the margins
scaberulous. Inflorescences terminal and axillary
from the uppermost nodes, partially included in
the sheaths; terminal inflorescences bearing male
spikelets only; axillary inflorescences bearing fe-
male spikelets, congested, few-flowered, the axis
and pedicels smooth, glabrous, to 2 mm long. Fe-
male spikelets 1.8-2.1 mm long, 0.5-0.6 mm
wide, narrowly ovoid, falling entire; glumes acu-
minate, short-hispid with long, thickened hairs
mainly on the nerves, the lower glume 3-nerved,
the upper glume 3-5-nerved; floret ca. 1.5 mm
long, narrowly ovoid (but none fully mature), whit-
ish, smooth, shiny. Caryopsis not seen. Maile spike-
lets 1.7-2 mm long, ca. 0.4 mm wide, lanceolate,
hyaline, glabrous, shiny; lemma 3-nerved; stamens
with anthers ca. 1 mm long.
Distribution and ecology. Endemic to wet
rocks near streams at low elevations in Mato Grosso
and Para, Brazil (Fig. 12).
Additional specimens examined. BRAZIL. MATO GROSSO:
Utiarity, Rio Papagaio, margin of waterfall, May 1918,
Kuhlmann 1866 'US). PARA: estrada Santar�m-Cuiab�,
877 km de Cuiab�, vale de solo pedregoso, embaixo da
Cachoeira da Luz do Rio Curu�, 8�45'S, 54�57'W, 350
m, 2 May 1983, Silva 196 (MO).
This species is related to R. potaroensis and R.
kaieteurana, but differs in its smooth female flo-
rets, and in female and maile spikelets of similar
size.
5. Raddiella minima Judziewicz & Zuloaga,
sp. nov. TYPE. Brazil. Para: Municipio de Itai-
tuba, km 771 estrada Santar�m-Cuiab�,
pr�ximo a divis�o Para-Mato Grosso, mata
de cerrado solo pedregoso, vegeta��o rupestre,
9�35'S, 54�35'W, 22 Apr. 1983, I.L. Ama-
ral, N. Silva, O.P. Monteiro, J. Lima, L.
Brako, W.D. Reese & M. Dibben 883 (ho-
lotype, INPA; isotypes, MO, NY).
A Raddiella esenbeckii differt lamina minore (4-6 x
2.7-3.3 mm) et spiculis mascula et femina minoribus (1-
1.3 mm longis), caryopside hilo punctiformi centrali prae-
dita.
Tiny, straggling herbs of indefinite duration.
Culms to 6 cm long, filiform, geniculate, multi-
branched, internodes purple, glabrous; nodes with
a few very short retrorse hairs. Leaves in loose
complements of 3-5; sheaths shorter than the in-
ternodes, usually shorter than the blades, glabrous
to short-pilose, 5-nerved, slightly inflated, the up-
per margins ciliate, abruptly truncate at the short-
ciliate summit; ligule membranous, ca. 0.2 mm
long; pseudopetiole 0.1-0.2 mm long, glabrous to
short-pilose; blades 4-6 mm long, 2.7-3.3 mm
wide, ovate-triangular, asymmetrical, glabrous, the
base truncate, the apex acute and apiculate, the
margins scaberulous, the abaxial surface occasion-
ally purplish. Inflorescences terminal and axillary,
terminal inflorescences 2-6, ca. 10 mm long, fi-
liform, each terminated by a single male spikelet;
axillary inflorescences 1 per each axil, ca. 3 mm
long, partly included in the leaf sheath, each of
2(-3) female spikelets on short, filiform pedicels.
Female spikelets 1-1.4 mm long; glumes lanceo-
late-ovate, acuminate, 3-nerved, glabrous to short-
hispid, persistent; floret 0.9-1.2 mm long, ovoid,
acute, dorsally compressed, smooth, shiny, white
becoming dark, deciduous; lemma 3-nerved. Cary-
opsis 0.7 mm long, 0.6 mm wide, ovoid-globose;
hilum punctiform, central; embryo small, basal.
Male spikelets ca. 1.3 mm long, the lemma soon
deciduous, elliptical, hyaline, glabrous; anthers ca.
0.6 mm long.
Distribution and ecology. Known only from
the type collection, made in campo rupestre near
the borders of the states of Mato Grosso and Para,
Brazil (Fig. 12).
Raddiella minima is related to R. esenbeckii,
but differs in its conspicuously smaller leaf blades
and maile and female spikelets; caryopsis with punc-
tiform, central hilum; and solitary maile spikelet
per inflorescence. It is not certain whether the
leaves exhibit sleep movements as in R. esenbeckii.
Along with the Cuban endemic Mniochloa pul-
chella (Griseb.) Chase, this species is one of the
world's smallest bambusoid grasses, hence its spe-
cific epithet.
939


Annals of the
Missouri Botanical Garden
6. Raddiella molliculma (Swallen) Calder�n
& Soderstrom, Smithsonian Contr. Bot. 44:
22. 1980. Panicum molliculmum Swallen in
R. Schultes, Bot. Mus. Leafl. 16: 57. 1953.
TYPE: Colombia. Caqueta (as "Vaup�s"): Cerro
de El Castillo, Rio Apaporis, moist, shaded
sandstone ledge with mosses and Selaginella
spp., 16 Jan. 1942, Guti�rrez & Schultes
616 (holotype, US*; isotype, COL). Figures
5, 6, 13H, I.
Delicate annuals. Culms decumbent, sprawling,
geniculate, the erect portions 5-10 cm tall, many-
noded, unbranched; internodes glabrous; nodes
compressed, short-pilose with retrorse hairs. Leaves
puberulent throughout with spreading, short-pilose
hairs; sheaths striate, shorter than the internodes,
the upper margins short-ciliate, the summit pilose;
ligules membranous-ciliate; pseudopetioles ca. 0.6
mm long, brownish, short-pilose; blades 7-12 mm
long, 3-4.5 mm wide, ovate-lanceolate, flat, deli-
cately membranous, slightly asymmetrical, the base
truncate, the apex acuminate, the margins sca-
berulous. Inflorescences terminal and axillary,
abundantly produced from the uppermost nodes
(6-15 from the terminal node), long-exserted on
glabrous, filiform peduncles 5 cm long; individual
inflorescences 2-5 mm long, few-flowered, with 1-
2 terminal, short-pedicelled maile spikelets and 1-
2 subterminal female spikelets or occasionally with
1 or more maile spikelets below; pedicels up to 1
mm long, glabrous. Female spikelets 1.3-1.5 mm
long, 0.6-0.7 mm wide, narrowly ellipsoid, falling
entire at maturity; glumes lanceolate-ovate, acu-
minate, subequal, greenish, short-hirsute, 3-nerved,
the lateral nerves inconspicuous; floret ca. 1.3 mm
long, 0.6-0.7 mm wide, ellipsoid, whitish, shiny,
papillose. Caryopsis 0.8 mm long, 0.6 mm wide,
ellipsoid, brownish; hilum oblong in the middle por-
tion of the caryopsis; embryo small, basal. Male
spikelets 1.3-2.2 mm long, 0.5-0.6 mm wide,
narrowly elliptical, acuminate, hyaline, short-his-
pid; lemma 3-nerved; stamens with anthers 0.9-
1.3 mm long, purple.
Distribution and ecology. Restricted to the
Cerro de El Castillo in Caquet�, Colombia (Fig.
12), at elevations of 240-300 m on moist, shaded,
sandstone cliffs.
Additional specimens examined. COLOMBIA.
CAQUETA: Upper Rio Apaporis basin, Cerro de El Castillo,
27 July 1943, Schultes 5668a (US), Grass1 10024 (US).
7. Raddiella potaroensis Soderstrom, Mem.
New York Bot. Gard. 12(3): 6. 1965. TYPE.
Guyana. Kaieteur Plateau, bottom of Potaro
Gorge near Kaieteur Falls to W rim of splash-
basin of Falls, 700 ft., 13 Mar. 1962, R. S.
Cowan & T. R. Soderstrom 2162 (holotype,
US*; isotypes, K, NY). Figures 7, 8, 13J-L.
Raddiella maipuriensis Soderstrom, Mem. New York
Bot. Gard. 12(3): 7. 1965. TYPE: Guyana. Imbai-
madai Savannas, Upper Mazaruni River, abundant
in spray of Maipuri Falls, Karaurieng River, 1,250
m, 25 Oct. 1951, B. Maguire & D. B. Fanshawe
32277 (holotype, US*; isotypes, NY, U).
Annuals. Culms weak, decumbent, branching
and rooting at the lower nodes, the flowering por-
tions 5-20 cm tall; internodes cylindrical, glabrous;
nodes thickened. Leaves with the sheaths longer
than the internodes, striate, glabrous, the margins
membranous, the apex somewhat truncate, one side
of the summit forming an auricle; ligules 0.2-0.4
mm long, membranous; pseudopetioles ca. 0.5 mm
long, glabrous; blades 9-17 mm long, 3-7 mm
wide, elliptical, flat, glabrous or with short, scabrid
hairs only on the veins, slightly acute and asym-
metrical at both ends. Inflorescences mainly axil-
lary (one terminal inflorescence in the type of R.
maipuriensis), 2-4 produced from each node, with
the bases included in the leaf sheaths or short-
exserted on peduncles less than 1 cm long, 2-3
spikelets per inflorescence, either ail female or the
terminal female and 1-2 maile spikelets below; ped-
icels of maile and female spikelets 1-3 mm long,
filiform, glabrous. Female spikelets 1.3-2.3 mm
long, ellipsoid to ovoid; glumes subequal, acute to
acuminate, sparsely hispid with spreading, strag-
gling hairs, weakly to strongly 3-5(-7)-nerved;
floret 1-1.3 mm long, 0.7-0.8 mm wide, ellipsoid,
acute, firmly coriaceous, shiny, whitish becoming
olivaceous at maturity, papillose; lemma 3-nerved.
Caryopsis ca. 0.9 mm long, 0.7 mm wide, slightly
obovoid; hilum punctiform in the middle portion of
the caryopsis; embryo ca. �4 the length of the
caryopsis. Male spikelets 2.7-4.2 mm long, 0.6-
0.7 mm wide, lanceolate, glabrous; lemma 3-nerved;
stamens with anthers 1.7-2 mm long.
Distribution and ecology. Apparently en-
demic to the Pakaraima Plateau of western Guyana
and adjacent Bolivar, Venezuela (two sterile col-
lections); on wet rocks near and in the spray zone
of waterfalls, from 200-1,250 m (Fig. 12).
Additional specimens examined. VENEZUELA.
BOLIVAR: Sierra de Lema, in tufts at base of uppermost
waterfall of headwaters of Rio Chican�n at base of high
sandstone NE-facing bluffs, headwaters of Rio Chican�n,
80 km SW of El Dorado, Stevermark 89568 (US); La
940

Volume 78, Number 4
1991
941
Zuloaga & Judziewicz
Revision of Raddiella
Gran Sabana, S of El Dorado along road to Santa Elena,
ca. km 202, Salto Cama, 1,000 m, Davidse 4872 (MO).
GUYANA. Kaieteur Falls, spray zone below falls, Apr. 1988,
Hahn et al. 4635 (BRG, US).
Judziewicz (1991) did not find enough differ-
ences between R. maipuriensis and R. potaroen-
sis to separate them as species and therefore placed
the first name in the synonymy of the latter. It
may be noted that the surfaces of the female florets
of both taxa are identical under the scanning elec-
tron microscope. The type specimen of R. mai-
puriensis is larger than the rest of the material
studied of this species, with culms ca. 20 cm tall,
leaf blades 2 cm long and 0.7 cm wide, and female
spikelets 1.8-2.3 mm long with acuminate, strong-
ly nerved glumes. Two sterile Venezuelan collec-
tions, Davidse et al. 4872 and Steyermark 89568,
are tentatively referred to this species based on
their nearly glabrous leaf blades.
EXCLUDED SPECIES
Raddiella truncata Swallen, Bull. Torrey Bot. Club
75: 89. 1948 [= Parodiolyra lateralis (Nees)
Soderstrom & Zuloaga)].
LITERATURE CITED
CALDERO�N, C. E. & T. R. SODERSTROM. 1980. The
genera of Bambusoideae (Poaceae) of the American
continent: keys and comments. Smithsonian Contr.
Bot. 44: 1-27.
DAVIDSE, G. & R. W. POHL. 1972. Chromosome num-
bers, meiotic behavior and notes on some grasses
from Central America and the West Indies. Canad.
J. Bot. 50: 1441-1452.
-- & - . 1978. Chromosome numbers of
tropical American grasses (Gramineae). Ann. Mis-
souri Bot. Gard. 65: 637-649.
JUDZIEWICZ, E. J. 1991. Family 187. Poaceae. In A.
R. A. Girts-van Rijn (editor), Flora of the Guianas,
Series A: Phanerogams. Koeltz Scientific Publica-
tions, Koenigstein, Germany.
SODERSTROM, T. R. 1965. Gramineae. In: B. Maguire,
The Botany of the Guayana Highlands, Part VI.
Mem. New York Bot. Gard. 12(3): 5-7.
& F. O. ZULOAGA. 1989. A revision of the
genus Olyra and the new segregate genus Parodi-
olyra (Poaceae: Bambusoidae: Olyreae). Smithsonian
Contr. Bot. 69: 1-79.
SWALLEN, J. R. 1948. Gramineae. In: B. Maguire et
al., Plant Explorations in Guiana in 1944, Chiefly to
the Tafelberg and the Kaieteur Plateau, I. Bull. Tor-
rey Bot. Club 75: 56-115.
ZULOAGA, F. O. 1987. Systematics of the New World
species of Panicum (Poaceae: Paniceae). Pp. 287
306 in T. R. Soderstrom et al. (editors), Grass Sys-
tematics and Evolution. Smithsonian Inst. Press,
Washington, D.C.