CHAPTER XV 



Tribe I. MAYDE^E 



This tribe is scarcely more than a division of the next 

 tribe, Andropogonea?, from which it differs in the se]5a- 

 ration of the staminate and pistillate inflorescences. The 

 structure of the spikelets in the 2 tribes is similar. 



Key to the Genera of Matde^ 



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 Tripsactjm 



(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) 



