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upper glume ; the lower glumes of the other spikelets free, much 

 smaller, membranaceous, ovate-lanceolate, acute, one-nerved, the flow- 

 ering glume shorter, three-nerved, tricuspidate ; palet two-nerved. 

 1. B. dactyloides, Engl. Buffalo grass. Mexico to British America. 

 This grass is extensively spread over all the region known as the 

 Great Plains. It is very low, the bulk of leaves seldom rising more 

 than 3 or 4 inches above the ground, growing in extensive tufts or 

 patches, and spreading largely by means of stolons or offshoots sim- 

 ilar to those of Bermuda grass, these stolons being sometimes 2 feet, 

 long, and with joints every 3 or 4 inches, frequently rooting and 

 sending up flowering culms from the joints. The leaves of the 

 radical tufts are 3 to 5 inches long, one or one-half line wide, smooth, 

 or edged with a few scattering hairs. The flowering culms are 

 chiefly dioecious, but sometimes both male and female flowers are 

 found on the same plant but in, separate parts. Next to the Grama 

 grass it is perhaps the most valuable grass in the support of the 

 cattle of the Plains. 



Pappophokum, Schreb. 



Spikelets in a dense spike-like, or narrow and loose, panicle, with 

 two to four approximate flowers, usually only the lowest perfect, the 

 others male or rudimentary ; outer glumes membranaceous, many- 

 nerved, awnless ; flowering glumes broader and thicker, convex on 

 the back, pubescent, produced above into nine to thirteen straight, 

 subulate awns ; palet smaller, two-keeled. 



1. P. apertum, Munro. Texas to Arizona. 



2. P. Wrightii, Watson. (P. boreale ?) Texas to Arizona. 



Cottea, Kth. 



Flowers in a loose contracted panicle ; spikelets six to nine flow- 

 ered, of which the two or three lower are perfect and the upper male 

 or neutral; outer glumes membranaceous, acute, convex on the back, 

 prominently many-nerved, one to three toothed at the apex ; rhachis 

 and base of flowers hairy ; flowering glumes broad, convex on the 

 back, somewhat five-lobed, nine to eleven awned, the awns straight 

 and unequal ; palet two-keeled, bifid at apex. 

 1. C. pappophoroides, Kth. Texas and Southwest. 

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