No. 23. 



ARISTIDA DIVARICATA H. B. K. 



Rootstocks not seen. Roots rather stout, branching only below. 



Culms tufted, erect, branching only at the base, 1 to 3 feet high, minutely re- 

 trosely scabrous, simple, most of its length taken up by the panicle. 



Leaves few, those of the stem 3 to 5; sheaths glabrous or minutely scabrous, 

 imbricated, usually with a few long hairs at the apex; ligule a row of short hairs, 

 with sometimes a few long ones intermixed; blades commonly 3 to 6 inches long, 

 involute, usually glabrous beneath and scabrous above, never hairy. Root leaves 

 similar, blades a little shorter. 



Inflorescence paniculate. Panicle usually 9 to 18 inches long, frequently sheathed 

 at the base; rachis nearly terete, glabrous; branches long (the lowest commonly 5 

 inches), widely spreading, naked at the base, flat, scabrous on the margins; spike- 

 lets borne singly, mostly short-peduncled, and appressed to the branches. 



Spikelets linear-subulate about 6 lines long (excluding the awns), somewhat 

 compressed. 



Glumes 3; first and second nearly equal, slightly spreading, narrowly linear, 

 acute, membranaceous, tawny and purple in color, compressed, 1-nerved, nerve 

 scabrous on the back; third (flowering) coriaceous, closely involute into a slender- 

 cylindrical tube, scabrous above, slightly shorter than the empty glumes, scarcely 

 twisted at the apex, produced into 3 straight, terete, scabrous, awns slightly 

 diverging when dry, two lateral ones about as long as the body of the glume, mid- 

 dle one from one-half to twice longer. Rachilla elongated, between second and 

 third glumes, to the length of ^ line, densely short- villous. 



Flower single, hermaphrodite. Palet minute, lanceolate, % line long. Lodi- 

 cules 2, shorter than the palet, linear-oblong. Stamens 3; anthers linear, line 

 long. Stigmas 2, cylindrical. 



Grain about 4 lines long, awl-shaped, tightly clasped by the flowering glume. 

 Rachilla disarticulating above the second glume. 



PLATE XXIII; a, spikelet, glumes spread apart and rhachilla separated at its 

 point of disarticulation. The hairs on the apex of the sheaths are not shown, nor 

 those on the rachilla above the second glume. The diameter of the tube of the 

 flowering glume is often nearly twice as great. 



Grows on dry or sandy hills and plains, extending to southern California. 



