HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 145 
Blades not elongated, about 10 times as long as wide. 
Culms soon prostrate, vine-like; branches divari- 
cate. 
Plants bright green; culms lax; spikelets not 
over 2.1 mm. long... iN: . 114. 
Plants grayish green; enim stiff; Epikolens 2. 5 
Too SNA onavaRLNG ran eh US A ENE A ue ease 115. 
Culms not vine-like; branches not divaricate. 
Spikelets 2.3 to 2.6 mm. long. 
Blades, or some of them, at least 8 mm. wide; 
fruit papillose-roughened. - Sa SW An i aL Oe 
Blades not over 6 mm. wide; att soos 
STACY TDN eae EUR eres) Mae SEE 167. 
Spikelets 2 mm. long. 
Culms wiry, crisp-puberulent; blades ciliate 
LUMO ASE entnven mak Ma RM a oh Nes a enue Ren pies 164. 
Culms glabrous; blades not ciliate. 
Blades erect, firm; spikelets turgid, 
strongly nerved; plants grayish olive. 112. 
Blades spreading; spikelets not turgid. 
Nodes glabrous; autumnal form erect, 
branched like a little tree........-- 109. 
Nodes, at least the lowest, usually 
bearded; autumnal form topheavy- 
: MECLUAITG sepa ye Saeco pia bs MII) 
Spikelets pubescent. Sa 
Spikelets 3 mm. or more long. - Pa yn. 
Blades elongated, those of the mid-culm at least 15 timesas 
long as wide. 
Secondary panicles from basal sheaths only. 
Spikelegs pointed, about 3.5 mm. long........-...-- 82. 
Spikelets blunt, 3 mm. or less long..-.-...........- 83. 
Secondary panicles from upper branches. 
Spikelets attenuate at base, pustulose-pubescent; 
lowermost sheaths softly villous. -.--- Na en 95. 
Spikelets not attenuate at base, not pustulose; lower- 
most sheaths glabrous or hispid. 
Upper leaves approximate; sheaths glabrous...... 187. 
Upper leaves distant; at least lower sheaths hispid. 180. 
Blades not elongated, usually less than 10 times as long as 
wide. 
Blades velvety-pubescent beneath. 
Spikelets 3mm. long; plants velvety-villous through- 
Spikelets 4 mm. or more long. 
Sheaths ascending-hirsute; ligule 3 to4 mm. long.. 173. 
Sheaths downy-pubescent; ligule obsolete........- 19]a. 
Blades not velvety-pubescent beneath. 
Sheaths glabrous or minutely puberulent only. 
Nodes bearded; spikelets 4 mm. or more long...... 191. 
Nodes not bearded; spikelets not over 3.8 mm. long. 
Spikelets 3.5 to 3.8 mm. long; blades 2 cm. or 
POLEMIC CRED ecto ae ic tnais) 2 uae aa 190. 
41616°—vo1t 15—10——10 
P. lucidum. 
P. sphagnicola. 
P. webberianum. 
P. patentifolium. 
P. lancearium. 
P. roanokense. 
P. dichotomum. 
P. barbulatum. 
Reis Vesna SQ rake Ke 
DSmrn , 
P. depauperatum. 
P. perlongum. 
P. fusiforme. 
P. equilaterale. 
P. aculeatum. 
A eas Wee hie OL 
P. raveneliv. 
P. boscit molle. 
P. bosewi. 
P. latifolium. 
