328 OHIO BIOLOGICAL SURVEY 



Tribe, Maydeae. Corn Tribe. 



Monecious grasses having the staminate and carpellate spikelets in 

 different inflorescences or in different parts of the same inflorescence, 

 often with highly specialized structures; spikelets articulated belozv the 

 empty glumes, round or dor sally compressed, in pairs, normally 2- 

 flowered, some of the flowers usually more or less vestigial or obsolete 

 and the staminate and carpellate flowers usually showing vestiges of 

 the opposite organs. 



66. Tripsacum L. Gama-grass. 



Tall stout monecious perennials with solid stems, thick creeping rhizomes, 

 broad flat leaves, and a panicle of spikate or racemose branches, the joints of 

 the fruiting rachis separating at the nodes, each joint containing a grain and the 

 remains of the spikelet, the upper part of the inflorescence staminate, lower part 

 carpellate. Staminate spikelets in pairs, the flowers containing vestigial ovularies ; 

 carpellate spikelet solitary imbedded in the rachis joint, with one carpellate flower 

 which contains vestigial stamens and a vestigial flower with only a vestigial 

 ovulary ; outer empty glume of the carpellate flower large and cartilaginous, the 

 inner coriaceous; flowering glumes hyaline; empty glumes of the staminate 

 spikelets subcoriaceous, the flowering glumes membranous or hyaline ; grain 

 free enclosed in the pocket of the rachis joint and the glumes. 



Tripsacum dactyloides L. Gama-grass. A monecious, perennial grass 

 with thick rhizomes and solid stems, 1-7 ft. high. Inflorescence consisting of a 

 number of spike-like racemes with paired staminate spikelets above and single 

 carpellate spikelets below. Spikelets 2-flowered, the carpellate spikelet, with one 

 carpellate and one vestigial flower, contained in the deeply channeled joints of 

 the rachis which separate spontaneously at maturity, by cleavage planes. 



Euchlaena mexicana Schrad. Teosinte. A monecious annual grass, 8-15 

 ft. high, of much value for forage in the south. The carpellate inflorescence 

 is surrounded by a peculiar husk, and the grains are enclosed in the flattened 

 rachis joints much as in Tripsacum. 



67. Coix L. Job's-tears. 



Coarse much-branched annuals with large broad leaves and a 

 monecious inflorescence, the staminate spikelets covered by a modi- 

 fied leaf-sheath which becomes bony and bead-like in fruit, the stam- 

 inate inflorescence projecting thru this sheath. Staminate spikelets 

 2-flowered, the flowers with vestigial ovularies; carpellate spikelets 

 2-flowered, the outer flower entirely vestigial with a lemma, the inner 

 containing a normal gynecium and 3 vestigial stamens ; two or more 

 vestigial structures usually present in the sheath besides the carpel- 

 late spikelet; empty glumes thick-membranous; flowering glumes 

 hyaline ; grain free, enclosed in the glumes and the bony sheath. 



1. Coix lacryma-jobi L. Job's-tears. A much-branched annual 

 grass with rather thick stems, 2-4 ft. high, and a pecular inflores- 



