144 
KEY TO SPECIES. 
Spikelets glabrous. 
Spikelets 3 mm. or more long, strongly nerved. 
Spikelets pointed, blades elongated 
Spikelets blunt, blades not elongated. 
Spikelets 3.2 to 3.3 mm. long; blades firm; sheaths, or 
some of them, hispid 
Spikelets not over 3 mm. long; blades rather thin; 
sheaths glabrous or sparsely hispid 
Spikelets less than 3 mm. long. 
Second glume and sterile Jemma exceeding the fruit and 
pointed beyond it; spikelets 2.2 to 2.9 mm. long. 
Blades clustered toward the base 
Blades not clustered toward the base. 
Sheaths, at least the secondary, hispid 
Sheaths glabrous. 
Blades iimimasy tr rae en) ey Ora epee ee eel 
Blades thin; fruit nearly 2 mm. long.............- 
Second glume and sterile lemma not pointed beyond the 
fruit. 
Ligule manifest, 1 to 3 mm. long. 
Culms rather stout; ligule 2 to 3 mm. long; sheaths 
SATAN ONO VOLS MAM aed AIO ete INE a Ne a eet gee 
Culms slender; ligule 1 mm. long; sheaths sparsely 
Ligule obsolete. 
Spikelets 1.5 mm. or less long. 
INodesibear dedi asia eee plier pd Caper EE 
Nodes not bearded. 
Culmsvandiiblad esol ose sere tee ee 
Culms glabrous. 
Blades conspicuously ciliate; plants branching 
fait; DAS@N Orally, se somes steers Ta OL A eens 89. 
Blades not ciliate; plants branching from mid- 
dle or upper nodes. 
Vernal culm 50 cm. or more high; spikelets 
turgid, strongly nerved; autumnal form 
erect, with fascicled branches shorter 
than the primary internodes. .........- 
Vernal culms usually much less than 50cm. 
high; autumnal form spreading or re- 
clining. 
Spikelets 1.1 to 1.2 mm. long; blades 
rarely as much as 5 cm. long..---.... 
Spikelets 1.2 to 1.4 mm. long. 
Blades elongated, at least some of them 8 
oul Orena lon ok Geen cee ce swe 
Blades not over 3 em. long...--.-..---- 
Spikelets 2 mm. or more long. 
Blades elongated, some of them 20 times as long as 
wide; spikelets 2.2 to 2.8 mm. long. 
Blades erect; branches, when present, from the 
lower nodes only 
85. 
Blades spreading; branches from upper nodes... 99. 
ss 
ry ty 
CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
. depauperatum. 
. scribnerianum. 
. helleri. 
. nudicaule. 
. scabriusculum. 
cryptanthum. 
. yadkinense. 
. Spretum. 
. curtifolium. 
. microcar pon. 
. strigosum. 
. polycaulon. 
. caerulescens. 
chamaelonche. 
. glabrifolium. 
. ensifolium. 
wernern. 
. bicknellit. 
