512 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM, 
Panicum TRIGONUM Retz.,’ an East Indian perennial with low creeping and 
branching culms and spreading pilose blades 2 to 4 cm.long, contracted panicles of 
short-pediceled hispidulous spikelets about 1.7 mm. long, the second glume keeled, 
the fruit slightly compressed laterally, has been found ‘‘under the shade of a shrub,” 
Port of Spain, Trinidad, Broadway 4891. / (tuyptlocecgern Lr a7, im 
Subgenus DICHANTHELIUM HBHitchce. & Chase. oe 
Foliage soft and lax, the flat blades prominently ciliate; ae 
plants branching from the base, finally forming ro- 
BEtLES Ol CUSITORS tse! si 2. eye es ary ere aes oe See LAxirLora, p. 513. 
Foliage not soft and lax; plants branching from the culm 
nodes. - 
First glume nearly as long as the spikelet........--. See Corpovensi, p. 525. / 
First glume much shorter than the spikelet. 
Spikelets glabrous; plants glabrous throughout; 
e autumnal form erect, not bushy-branching. See DicHoroma, p. 516. 
Spikelets pubescent. 
Sheaths glabrous or minutely puberulent 
onl¥; ligules minute or obsolete. 
Spikelets attenuate at base, mostly 
prominently pustulose; blades 
narrow, stiff, strongly nerved, ta- _ 
pering from base to apex......-.. See ANGustiroLta, p. 514. 
Spikelets not attenuate at base, not pus- 
tulose. 
Spikelets subglobose or pyriform. 
Blades spreading, rarely over 5 
em. long and 5 mm. 
wide, spikelets pyriform; 
autumnal form bushy- \ 
branching =.) 557% nee See LANCEARIA, p. 522. ~ 
Blades erect, 7 to 13 cm. long, 
7 to 14 mm. wide; spike- 
lets/spheroid 2. .-2-2222 See SPHAEROCARPA, p. 521. 
Spikelets not subglobose nor pyri- 
form. 
Spikelets 2.8 mm. or more long. See CommuTara, p. 524. 
Spikelets not over 2 mm. long. 
Blades with a cartilaginous 
white margin; spike- 
lets not over 1.5 mm. 
Lone: Rie tee “Sem ere 101. P. albomarginatum. 
Blades not white-margined; 
spikelets 2mm.long. See DicHoroma, p. 516. 
Sheaths pubescent. 
Spikelets 4 mm. long, pyriform......-- 104. P. nodatum. 
Spikelets not over 2.6 mm. long. 
Spikelets attenuate at base, mostly 
prominently pustulose; blades 
narrow, stiff, strongly nerved, 
tapering from base to apex; 
autumnal form often bushy- 
branched te ngs ea eee See AN@uSTIFOLIA, p. 514. 
1Obs. Bot. 3: 9. 1783. 
