GRASSES OF OHIO 
263 
((!)). Lemma not coriaceous in fruit; grain beakless, not ex- 
serted. 
a, Rachilla not prolonged behind the palet of the uppermost 
sterile flower; spikelets in an open panicle. 
' Eragrostis. (7) 
b. Rachilla prolonged behind the palet of the uppermost 
flower; spikelets 2-5-flowered, usually in a more or less 
contracted panicle. 
(a) . Inner empty glume broad and rounded at the tip; 
very dissimilar from the outer glume. 
Sphenopholis. (8) 
(b) . Inner empty glume similar to the outer. 
Koeleria. (9) 
((2)). Lemma coriaceous in fruit, grain beaked and exserted. 
Korycarpus. (10) 
(2). Callus and nerves of the lemma densely bearded, not cobwebby. 
((1)). Palet not ciliate-fringed; internodes of the rachilla short. 
Tridens. (11) 
((2)). Palet conspicuously ciliate-fringed; internodes of the 
rachilla long. Triplasis. (12) 
B. Spikelets of 2 kinds, in small clusters, the upper perfect ones surrounded 
by sterile spikelets below. Cynosurus. (13) 
II. Rachilla with hairs longer than the flowering glumes. Phragmites. (14) 
Aveneae. 
I. Spikelets not deciduous, the empty glumes persistent. 
A. Spikelets 2-many-flowered; rachilla prolonged beyond the upper glume. 
1. Awn projecting from between the lobes of the lemma, flattened and 
twisted. Danthonia. (15) 
2. Awn of the lemma dorsal, not flattened. 
(1) . Spikelets 2-flowered, the upper bisporangiate, the lower staminate 
and its glumes strongly awned. Arrhenatherum. (16) 
(2) . Spikelets 2-several-flowered; flowers all bisporangiate or the 
uppermost imperfect.. 
a. Lemma keeled; awn rising from above the middle; spikelets 
less than Yi inch long. Trisetum. (17) 
b. Lemma rounded on the back. 
(a) . Spikelets over ^2 in. long; grain furrowed, usually ad¬ 
herent to the flowering glumes. Avena. (18) 
(b) . Spikelets less than ^ in. long; grain not furrowed, free. 
Deschampsia. (19) 
B. Spikelets with 2 bisporangiate flowers; rachilla not prolonged beyond the 
upper flower. Aspris. (20) 
II. Spikelets deciduous; lower flower bisporangiate, upper staminate with a hook¬ 
like awn; plant velvety. Nothoholcns. (21) 
