186 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 
Second glume and sterile lemma 
neither many-nerved, saccate, 
auriculate, nor lyre-shaped; 
subtending bristles 1 tomany. 46. CHABTOCHLOA (p. 259), 
Spikelets not subtended nor surrounded 
by bristles (axis of branchlet ex- 
tending beyond the base of the 
uppermost spikelet as a point or 
\ bristle in Panicum, subgenus 
Paurochaetium), 
Fruit cartilaginous-indurated, not 
rigid, papillose, usually dark- 
colored, the more or less prom- 
inent white hyaline margins of the 
lemma not inrolled. 
Fruit open at the hyaline summit.. 26. LeprocoryPHIvM (p. 218). 
Fruit not open at summit. 
Fruit lanceolate, acuminate; sec- 
ond glume and sterile lemma 
usually long-silky.........2.. 27. VaLoTa (p. 218). 
Fruit elliptic; pubescence short 
or none, 
Inflorescence of slender ra- 
cemes, digitately or sub- 
digitately arranged........ 28. SYNTHERISMA (p. 219). 
Inflorescence a capillary pan- 
icle...... 2.2.20... eee eee ee 29. LeEproLoma (p. 222). 
Fruit indurated, rigid (or if thin the 
lemma not hyaline-margined). 
Spikelets (or the primary one of a 
pair) placed with the back of 
the fruit turned away from the 
rachis, usually solitary. 
First glume as long as the spikelet 
or nearly so; spikelets in 
pairs, the secondary usually 
aborted, sometimes wanting, 
strongly tuberculate-hispid or 
uncinate at maturity, later- 
ally compressed, in unilateral 
TACEMOS.........22 2c eee eee 30. EcHINOLAENA (p. 223). 
First glume obsolete or not over 
one-fourth the length of the 
spikelet. 
Rachilla joint and first glume 
forming a swollen ring-like 
callus below the spikelet, 
the glume reduced to an ad- 
nate sheath of the rachilla 
joint; fruit mucronate or 
awn-tipped.............. 31. Ertocu1oa (p. 223). 
" Rachilla joint not forming a 
ring-like callus below the 
spikelet; first glume pres- 
ent or wanting. 
