GRASSES OF OHIO 
269 
35. Lemma broad, glabrous, its awn deciduous; callus short, obtuse. 
Oryzopsis (47) 
35. Lemma narrow; its awn persistent; callus usually acute. Stipa. (48) 
36. Spikelets with a terminal perfect flower and 2 staminate lateral flowers, 
Savastana. (50) 
36. Spikelets with but 1 flower and sometimes with mere vestiges of lateral 
flowers. 37 
37. Empty glumes very unequal; stamens 2; third and fourth glumes (above the 
two empty glumes) awmed upon the back. Anthoxanthum. (52) 
37. Empty glumes equal; stamens 3; third and fourth glumes small and ves¬ 
tigial not awned. Phalaris. (51) 
— 38 — 
38. Spikelets monecious, the staminate and carpellate spikelets in different parts 
of the inflorescence. 39 
38. Spikelets not monecious; staminate spikelets if present distributed among the 
perfect ones. 40 
39. Staminate and carpellate spikelets much alike in appearance, intermixed in 
the panicle, but the staminate at the top of the branches. Zizaniopsis. 
39. Staminate spikelets in the lower part of the panicle; the carpellate above, 
unlike in appearance. Zizania. (61) 
40. Inflorescence a compact spike-like panicle. 41 
40. Inflorescence a loose panicle or with slender branches. 42 
41. With an involucre of bristles about the base of the spikelets. 
Chaetochloa (58) 
41. Spikelets without a subtending involucre of bristles. Alopecurns. (41) 
42. Spikelets laterally compressed. 43 
42. Spikelets round, or dorsally compressed. 45 
43. Spikelets 2-3-flowered; empty glumes dissimilar. Sphenopholis. (8) 
43. Spikelets 1-flowered. 44 
44. Glumes 4; lemma with a short awn between the bifid apex. China. (39) 
44. Glumes only 2, without awns. Homalocenchnts. (60) 
45. Flowering glumes chartaceous or coriaceous, differing from the membranous 
empty glumes. 46 
45. Flowering glumes thin and hyaline, usually much more delicate than the 
empty glumes. 48 
46. Margins of the fruiting flowering glumes hyaline and flat. Leptoloma. (54) 
46. Margin of the fruiting lemma inrolled and not hyaline. 47 
47. Sterile lemma awned or pointed; spikelets crowded in 1-sided racemes which 
are arranged in a panicle. Echinochloa. (56) 
47. Empty glumes and lemmas awnless; spikelets usually in panicles. Panicum (53) 
48. Stem solid. 49 
48. Stem hollow. 50 
49. Sessile spikelets perfect the stalked spikelet vestigial, spikelets on the ends 
of slender branches of a spreading panicle. Holciis. (62) 
49. Spikelets all perfect; arranged in pairs along the continuous branches of the 
panicle. Miscanthus. (64) 
50. Lemma with a hooked dorsal awn, spikelets in a loose panicle; plant softly 
pubescent.^ _ Nothoholcus. (21) 
50. Lemma with a prominent terminal awn; spikelets in a slender panicle; leaves 
scabrous and glaucous, the sheaths smooth. Sorghastrum. (63) 
— 51 — 
51. Spikelets not covered with a prickly bur. 52 
51. Spikelets covered with a prickly bur. 
Cenchrus. (59) 
