No. 18. 

 ANDROPOGON CIRRHATUS Hackel. 



Rootstock short. Roots strong. 



Culms tufted, 2 to 3 feet high, slender, branching above, of 6 to 8 joints ; lat- 

 eral branches arising singly, slender, becoming long-exserted. 



Leaves. Sheaths narrow, close, smooth, striate ; ligule short, truncate, smooth; 

 blade 3 to inches long, 1 to 2 lines wide, attenuated to a long acute point, rigid, 

 smooth, except the roughish margins. 



Inflorescence terminal on the culm and its branches, in a spike-like raceme 

 about 2 inches long consisting of 10 to 15 joints; rachis smooth. 



Spikelets in pairs. Female spikelets sessile, about 3 lines long ; first glume 

 linear-lanceolate, thick, 2-toothed at apex, smooth except the scabrous keel and 

 margins, 7- to 9-nerved; second glume slightly shorter than the first, acute, much 

 thinner, 3-iierved above, smooth; third glume one-fourth shorter than the first, 

 hyaline, linear-oblong, obtuse. 2-uerved, ciliate on the margins; fourth glume as 

 long as the third, hyaline, bifid, attached below to an awn 6 to 8 lines long. Male 

 spikelet rather shorter than the female, about equaling its pedicel; pedicel smooth 

 except a tuft of cilia near the apex; glumes 4, much as in the female, but without 

 the awn of the third glume. 



PLATE XVIII; a, pair of spikelets; 5, female spikelet opened to show the 

 parts; c, male spikelet opened. 



This is related to the broomsedge (A. scoparius), and is rather rare. 



