No. 19. 

 ANDROPOGON HIRTIFLORUS Kunth. 



Culms 3 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 fi inches long, 1 to 3 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 30 joints, 2 to 3 inches long; branches 

 slender, long-exserted from the sheaths. 



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

 fertile, upper sterile. Perfect s^jikelet 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 ; 6, perfect flower with the glumes spread out. The outer or first glume 

 does not show the long hairs. 



This species also is related to ^4. scoiMrius. It is found on rocky hills in 

 westei'n Texas, in the Santa Catalina and Huachuca Mountains of Arizona, and in 

 Mexico. 



