r 



CHAPTER XV 

 Tribe I. MAYDE^E 



This tribe is scarcely more than a division of the next 

 tribe, Andropogonese, from which it differs in the sepa- 

 ration of the staminate and pistillate inflorescences. The 

 structure of the spikelets in the 2 tribes is similar. 



Key to the Genera of Mayde^ 



A. Staminate and pistillate spikelets in separate 

 inflorescences, the former in a terminal 

 tassel, the latter in the axils of the leaves. 



B. Pistillate spikes distinct, articulated Euchl^na 



BB. Pistillate spikes grown together forming (Par. 201). 



an ''ear" , Zea (Par. 202). 



aa. Staminate and pistillate spikelets in separate 



portions of the same spike, the pistillate 



below. 



B. Spikes short, the 1- to 2-flowered pistillate 



portion inclosed in a bead-like sheathing 



bract .Coix(Par.203). 



BB. Spikes many-flowered, the pistillate portion 

 breaking up into several 1-seeded joints; 



no bead-like sheathing bract Tripsacum 



(Par. 200). 



200. Tripsacum L. — The terminal inflorescence con- 

 sists usually of a cluster of spikes the lower portions of 

 which are pistillate and the upper portions staminate. 

 The pistillate portion consists of a series of joints which 

 disarticulate at maturity forming bony cylindrical or 

 angled seed-like parts made up of the thick axis and an 

 imbedded spikelet. The spikelet consists of a hard first 

 glume which closes the spikelet within the joint of the 

 rachis, a thinner second glume, a sterile lemma with a 



(159) 



