HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 
Culms single or few in a tuft; spikelets turgid, 2.7 to 3 
TRUE OTC edepsE Cee cc SS i OE CN 
Culms in large tufts; spikelets not turgid, not over 2.7 
mm. long. 
Sheatnsnpiloseriemeceranepe keys, Goi) ll a 84, 
85. 
Sheapnesslabrous sea eeasen say eae asa. Ya oo) 
Blades usually not elongated; secondary panicles not at 
the base. 
Spikelets attenuate at base, mostly prominently pustu- 
lose; blades narrow, stiff, strongly nerved, tapering 
from base to apex. 
Nodes bearded; plants grayish-villous; autumnal 
blades flat. 
Spikelets imme ylongees keeles 
Spikelets 2eartop. 8 mmdomo ws ihe n OU ale oe 
Nodes not bearded; plants villous only at the base, or 
nearly glabrous. 
Autumnal blades flat; lower panicle branches 
spreading or deflexed..........-.-. Bela Make NL 
Autumnal blades involute; lower panicle branches 
more or less ascending. 
Plants glabrous or nearly so; autumnal culms 
erect. 
Spikelets subsecund along the suberect panicle 
Onze OC OV EYL A SAMRAT Ve Eh WAR ISR NMC AID ILA IE 8s 98. 
Spikelets not subsecund; panicle loose and 
Plants pubescent, at least on the lower half. 
Spikelets about 2.4 mm. long; vernal blades 7 
to 12cm. long, autumnal blades not faleate. 96. 
Spikelets not over 2 mm. long; vernal blades 
4 to 6 cm. Jong, autumnal blades falcate.. 91. 
Spikelets not attenuate at base. 
Sheaths retrorsely pilose; blades soft and lax. 
Panicle branches ascending, forming a compact 
panicle; spikelets 1.6 mm. long.............- 
Panicle branches loosely spreading. 
Blades ciliate and more or less pilose on the sur- 
face wspikeletsi2 mm ono ses us sae ls 87 
Blades glabrous or nearly so on the surface and 
margin; spikelets 2.2 mm. long. ........-..- 86. 
Sheaths not retrorsely pilose. 
Ligule manifest, mostly 2 to 5 mm. long. 
Sheaths, or all but the lowest glabrous; spike- 
lets not over 1.6 mm. long. 
Panicle narrow, one-fourth to one-third as wide 
CRS OTR NA cred tat ely nA a STE nro oe 116. 
Panicle open, nearly as wide as long. 
Spikelets leo mm, long 222020. .2 a. eet 117. 
Spikeletsed mim long. lle. 5 fee LO) 
Sheaths pubescent. 
Oar 
ate 
Jive 
nr ge 
147 
. perlongum. 
. Linearvfolium. 
. werner. 
. chryso psidifo- 
lium. 
. consanguineum. 
. angustifolium. 
neuranthum. 
. ovinum. 
. arenicoloides. 
. aciculare. 
. xalapense stric- 
tirameum. 
xalapense. 
. laxiflorum. 
. Spretum. 
. lindheimeri. 
. longiligulatum. 
