266 
OHIO BIOLOGICAL SURVEY 
Paniceae. 
I. Spikelets without a subtending involucre. 
1. Spikelets arranged in true panicles. Panicum. (53) 
2. Spikelets arranged in 1-sided recemes, sometimes paniculate. 
(1) . Fruiting flowering glumes chartaceous, with flat hyaline margins. 
a. Spikelets long-pediceled, in a diffuse pinacle. Leptoloma. (54) 
b. Spikelets on slender spike-like, often digitate branches of the in¬ 
florescence. Syntherisma. (55) 
(2) . Fruiting flowering glumes indurated, rigid, the margins inrolled, not 
hyaline. 
a. Some of the glumes awned; spikelets crowded in 1-sided branches 
of the panicle. Echinochloa. (56) 
b. Glumes awnless; spikelets plano-convex, on secund branches of the 
inflorescence. Paspalum. (57) 
II. Spikelets with an involucre of bristles or a prickly bur. 
1. Spikelets subtended by bristles. Chaetochloa. (58) 
2. Spikelets enclosed in a globular, prickly, bur-like involucre. Cenchrus. (59) 
Oryzeae. 
1. Spikelets much flattened laterally, with bisporangiate flowers. 
Homalocenchrus. (60) 
2. Spikelets monosporangiate. 
a. Spikelets intermixed in the panicle. Zizaniopsis. 
b. With carpellate spikelets in the upper part of the panicle and staminate 
spikelets below. Zizania. (61) 
Andropogoneae. 
1. Inflorescence paniculate, decompound. 
a. Pedicellate spikelet present; stem solid. Holcus. (62) 
b. Pedicellate spikelet wanting; stem hollow. Sorghastriim. (63) 
2. Inflorescence simple or compound made up of 1 or more spike-like racemose 
branches. 
a. Spikelets alike, all with bisporangiate flowers; rachis of the inflorescence 
branches continuous. MiscantJnis. (64) 
b. Sessile spikelets bisporangiate, with awns, the pedicellate spikelets staminate 
or empty; inflorescence simple or with 6 or less digitate branches. 
Andropogon. (65) 
Maydeae. 
1. Carpellate spikelets inclosed in pockets of the internodes of the enlarged and 
flattened rachis; rachis breaking into joints at maturity; inflorescence stam¬ 
inate above, carpellate below. 
a. Carpellate inflorescence not covered with husks. Tripsacum. (66) 
b. Carpellate inflorescence covered with husks. Euchlaena. 
2. Carpellate spikelets covered by a bony leaf-sheath or collected in an ear covered 
with husks. 
a. With a bony leaf-sheath covering the single large grain. Coix. (67) 
b. With numerous grains in an ear covered with husks, or with husk-like 
glumes around the grains. Zea. (68) 
