6 GRASSES OF IOWA. 



Spikelets in two (rarely more) opposite rows forming an equilateral 



spike (very rarely unilateral) XII. HORDEAE. 



b. Culm (at least at the base) woody, leaf-blade often with a short 

 slender petiole articulated with the sheath from which it finally separates. 



—XIII. BAMBUSEAE. 



TRIBE 1.— MAYDE^E. 



Spikelets unisexual, the 

 [i v >^ // staminate forming a part of 



IQi \. ^^y^y/ .lUy the inflorescence with the pis- 



\ ■ it) sr t^^^j or eacn m a separate in- 

 . Ill) S ry . florescence on the same plant ; 

 flowering glumes hyaline or 

 much less firm in texture than 

 the outer ones; axis of the fe- 

 male spikelet usually articu- 



Fig. 1. Fertile flower— Maize [Zea Mays), lated. 



(Charlotte M.King.) ^ ^ Maydeae c(m _ 



tains sixteen species distributed in seven genera, and is remarkable for a 

 number of monotypic types. They are native to the tropics. The best 

 known illustrations are maize and Euchlaena. 



KEY TO THE GENERA OF THE MAYDEAE. 



A. Staminate and pistillate spikelets in separate inflorescences, the staminate 

 above. 



Staminate spikes numerous in terminal panicles. Pistillate spikes many- 

 flowered, axillary, subtended by large, leaf-like bracts. 



Pistillate spikes in each axil fasciculate, distinct, rachis of each articu- 

 lated EUCHLAENA. i. 



Pistillate spikes in each axil united, forming a compound spike with much 



thickened continuous axis ZEA. 2. 



Staminate spikes solitary, pistillate spikes usually reduced to a single spike- 

 let, enclosed by an indurated sheath COIX. 3. 



B. Staminate and pistillate spikelets in the same spike the staminate above. 



— TRIPSACUM. 4. 



1. EUCHLAENA. 



Euchlaena Schrad. Ind. Sem. Hort. Goett. 1832 Benth. and Hook. Gen. 

 PI. 3: 1114. Hackel in Eogler & Prantl. Nat. Pllanz. Fam. II. 2: 19. 

 Scribner. Bull. U. S. Dept. Agrl. Div. Agros. 20: 11. fl. 



DESCRIPTION. 



Teosinte. Spikelets unisexual, monoecious; the staminate two- 

 flowered in pairs, one sessile, the other pedicellate, along the numerous 

 paniculate racemes; the pistillate i-flowered, sessile and solitary at each 



