GRASSES OF OHIO 271 



71. Spikelets strictly 1-flowered; branches of the inflorescence in our species 



usually numerous. Spartina. ( 2 ( .) ) 



71. Spikelets with 1 perfect flower and 1 or more vestigial ones; branches of the 

 inflorescence 4 or less. Bouteloua. (34) 



72. Carpellate spikelets in pockets of the rachis ; inflorescence without husks or 

 hardened leaf-sheaths. Tripsacum. (66) 



72. Carpellate spikelets covered with husks or with the thickened subtending 

 leaf sheath. 73 



73. Carpellate spikelets covered by a hardened leaf -heath, forming a bead-like 

 fruit. Coi.v. I 67 I 



73. Carpellate spikelets in rows on a cob, usually covered with papery husks. 



Zea. (68) 



