24 KEY TO THE TRIBES 



Flowering plumes parery to leathery, very 

 different In color and appearance from 



the empty glumes. Till)'- III. Paniceae. 



€pikelets with the rachilla jointed above the 

 empty glumes which persist, 1- to many- 

 flowered: frequently the upper glumes are 

 empty; rachilla often prolonged beyond the 

 upperglume. 

 Spikelets borne in an open or spike-like pan- 

 icle or raceme, usually upon distinct 

 pedicels. 

 Spikelets 1-flowered. 

 Empty glumes 4: palet l-nerved. Tribe IV. Phalaridexh 



Empty glumes 2, rarely 1; palet 2- 



nerved (except In Cinna). Tribe Y. Agrostideae. 



Spikelets 2- to many-flowered. 



Flowering glumes usually shorter than 

 the empty glumes: the awn dorsal 



and usually bent. Tribe VI. Aveneab. 



Flowering glumes usually longer than 

 the empty ones; the awn terminal 



and straight or none. Tribe VIII. Festuceab. 



Spikelets in two rows, sessile or nearly so. 

 Spikelets on one side of the continuous 



axis, forming one-sided spikes. Tribe VII. Chlorideab. 



Spikelets alternately on opposite sides of 



the axis which is often jointed. Tribe IX. Hordeae. 



