128 



Fig. 97. Triodia eragrostoides Vasey & Scribn.— a, A spikelet; b, the same 

 with the empty glumes separated from the florets c, above, d, dorsal view of a 

 flowering glume; e, palea. Figs. 231 to 236, in Bui. 7, and 505 to 507, in Bui. 17, 

 illustrate other species of this genus. 



97. TRIODIA R. Br. Prod. PI. Nov. Holl., 182. 1810. Spikelets 3- to 12- flow- 

 ered, nearly terete, in strict or open panicles; rachilla articulated between the 

 florets, smooth or short-pilose; florets hermaphrodite or the uppermost stam- 

 inate. Empty glumes 2, unequal, somewhat keeled, shorter than the spikelet; 

 flowering glume membranaceous or subcoriaceous, rounded on the back at 

 least below, 3-nerved, 2- to 3-toothed or pointed; nerves, especially the mar- 

 ginal, silky-villous below and extending (in our species) between the teeth at 

 the apex into 3 mucronate points. Palea broad, concave, with 2 nearly mar- 

 ginal nerves. Stamens 3. Styles short, stigmas plumose. Grain free. Peren- 

 nial grasses with narrow leaves and variable habit. 



Species about 25, widely distributed throughout the temperate zones, with a 

 few in tropical America. Nearly half the entire number of species occur in the 

 United States, chiefly Texas and the Southwestern Territories. 



