DESCRIPTIONS OF TRIBES AND GENERA. 15 



parted and ending in awns ; middle awn flattened at the 

 base, usually geniculate and twisted. 



Species about one hundred, in the warm and tem- 

 perate zones of both hemispheres, more than half of them 

 in South Africa. [D. compressa Austin, on the moun- 

 tains of North Carolina and Tennessee, is valuable for 

 grazing.] 



Sec. I. Himantochcete. The two teeth of the flower- 

 ing glume undivided. D. provincialis DC. (Fig. 66), 

 from South Europe to Vienna. Crinipes Hochst. and 

 Streblochcete Hochst. are species of this section. 



Sec. II. Pentaschistis. Teeth of the flowering glumes 

 again two-toothed and often produced into awns. Pen- 

 tameris Beauv. and Chcztobromus Nees belong here. 



TEIBE X. CHLORIDES. 



Spikelets one- to many-flowered, in two series upon the 

 outer side of the continuous rachis of the spike or raceme ; 

 flowering glumes deciduous with the fruit ; the usually 

 two empty glumes rarely falling with them. Palea two- 

 nerved ; styles distinct ; stigmas projecting from the 

 sides, rarely from just below the apex, of the spikelets ; 

 grain free, unfurrowed ; starch-grains usually compound, 

 rarely simple. 

 A. Flowers of all the spikelets hermaphrodite. 



a. One $ flower (very rarely two) in each spikelet. 

 a. No sterile glumes or $ flowers, and only rarely 

 a short projection above the flower. 

 I. Spikelets awnless [sometimes short-awned 

 in Spartind], 



1. Spikelets falling off from the rachis entire. 



17O. Spartina. 



2. Empty glumes not deciduous. 

 * Spike terminal, slender. 



168. Michrochloa. 



** Spikes 2-6, digitate. . 169. Cynodon. 

 *** Spikes many along a common axis, 

 t The axis slender ; flowering glume 

 longer than the empty ones. 



179. Schedonnardus. 



