122 



GRASSES OF IOWA. 



DISTRIBUTION. 



Iowa. Wapsipinicon River (31, E. N. Wilcox). 

 North J /iierica. Iowa to Texas and Mississippi. 



7. ARISTIDA GRACILIS. 



Aristida gracilis Ell. Bot. S. C. and Ga. 1: 142. 1817. Watson and 

 Coulter. Gray. Man. Bot. 640. Scribner. Grasses of Tenn. Bull. Univ. 

 Tenn. Agrl. Exp. Sta. 7: 64. /. 74. 1894. Beal. Gra ses N . A. 2: 209. 1896. 

 Nash in Britton and Brown, 111. PI. 1: 133. / 298. 1896. Vasey Contr. 

 U. S. Nat. Herb. 3: 44. 



Aristida gracilis var. depauperata. A. Gray. Man. 618. 1867. (5th ed.) 



description-. 



Slender Aristida. A slen- 

 der, erect grass, 12 to 24 inches 

 (24-48 cm.) high, branched 

 near the base, the culms and 

 branches terminating in slender, 

 rather densely-flowered, racemose 

 or spike-like panicles 3 to 7 

 inches (6-14 cm.) long. Rays 

 of the panicle in pairs, erect, 

 one to several-flowered. Sheaths 

 smooth or pilose near the base ; 

 ligule a minute fringe of short 

 hairs; leaf-blade 3 to 5 inches 

 (6-II cm.) long, about 1 line 

 (2 mm.) wide, soon convolute. 

 Spikelets 2 to 3 lines (4-6 mm.) 

 long (exclusive of the awns) ; 

 empty glumes one-nerved, nar- 

 rowly lanceolate, nearly equal, 

 or the lower one a little shorter 

 than the upper which is usuallj 

 short awned or mucronate* 

 pointed; flowering-glume usually 

 a little longer than the empty 

 ones, rough and usually spotted 

 on the back, three-awned, the 

 lateral awns straight, and one- 

 third to one-half the length of 



the divaricate or reflexed middle one. Callus hairy. In sandy, gravelly 



or poor soils. September-October. 



Fig. 88. Aristida gracilis. Uoper right 

 hand figure spikelet. (Charlotte M. King.) 



