No. 19. 

 ANDROPOGON HIRTIFLORUS Kunth. 



Culms 2 to 4 feet high, densely tufted on a short rootstock, erect, rather slen- 

 der and wiry, with generally single branches from the upper joints; lower inter- 

 nodes compressed, furrowed on the inner face ; branches becoming long-exserted 

 and flower-bearing at the extremity, smooth. 



Leaves crowded below, distant above ; lower sheaths compressed, short, with 

 scattering hairs or nearly smooth ; ligule membranaceous, short, truncate ; blade 

 flat, 2 to 6 inches long, 1 to 2 lines wide, firm and erect, rather scabrous, acumi- 

 nate. 



Inflorescence terminating the culm and branches as a loose, narrow, few-flow- 

 ered, spike-like raceme, consisting of 10 to 20 joints, 2 to 3 inches long ; branches 

 slender, long-exserted from the sheaths. 



Spikelets in pairs at the joints of the flattened hairy rachis, lower perfect and 

 fertile, upper sterile. Perfect spikelet 4 lines long ; glumes 4, two of hard texture 

 and two hyaline ; first linear-lanceolate, roughened on the back, covered with long 

 white hairs ; second thinner, keeled, without hairs, minutely scabrous ; third 

 hyaline, a little shorter than the second, slightly ciliate, deeply bifid, attached be- 

 low to its twisted and bent awn, which is 8 or 10 lines long ; fourth hyaline, entire, 

 inclosing the proper flower. Sterile spikelet: pedicel about 2 lines long, flattened, 

 cilate ; glumes generally 2; first lanceolate, acuminate, green, thick, hirsute; second 

 hyaline, inclosed by the first. 



PLATE XIX; a,, pair of spikelets, the perfect one sessile, and the sterile one on 

 a pedicel ; b, perfect flower with the glumes spread out. The outer or first glume 

 does not show the long hairs. 



This species also is related to A. scoparius. It is found on rocky hills in 

 western Texas, in the Santa Catalina and Huachuca Mountains of Arizona, and in 

 Mexico. 



