182 



GRAMINEAE. 



VOL. I. 



ii. Aristida intermedia Scribn. & Ball. Plains 

 Aristida. Fig. 433. 



A. intermedia Scribn. & Ball, Bull. U. S. Dep. Agr. 

 Agrost. 24: 44. 1901. 



Culms slender, finally branching, i-2$ tall; 

 sheaths glabrous or sparsely hirsute; blades 2'-6' 

 long, i" wide or less, erect, involute ; panicle 8'-i6' 

 long, slender, its branches appressed ; spikelets 4" -5" 

 long, the empty scales manifestly awned, about equal, 

 the flowering scale strongly hispidulous above the 

 middle, equalling or exceeding the empty scales, the 

 awns spreading, the middle one 7"-i3" long, the 

 lateral ones shorter. 



In sandy soil, Iowa and Kansas to Mississippi and 

 Texas. Aug.-Oct. 



12. Aristida purpurascens Poir. Arrow-grass. 

 Broom-sedge. Fig. 434. 



Aristida purpurascens Poir. in Lam. Encycl. Suppl. i : 

 452. 1810. 



Glabrous and smooth, culms i-2j tall, erect, simple 

 or sparingly branched at the base. Sheaths longer than 

 the internodes, crowded at the base of the culm; ligule 

 very short; blades 4'-8' long, about i" wide, flat, or 

 becoming involute in drying, attenuate into a long 

 point ; spike-like panicles 5'-i8' long, strict, or some- 

 times nodding, its branches appressed; outer scales of 

 spikelet awn-pointed, the first longer than the second ; 

 the third scale from two-thirds to three-quarters as 

 long as the first, middle awn p"-i2" long, horizontal, 

 the lateral awns somewhat shorter, 'erect or divergent. 



In dry soil, Massachusetts to Minnesota, south to 

 Florida and Texas. Sept.-Oct. 



13. Aristida lanosa Muhl. Woolly Triple-awned Grass. Fig. 435. 



Aristida lanata Poir. in Lam. Encycl. Suppl. 1 : 453. 1810. 

 Not Forsk. 1775. 



Aristida lanosa Muhl. Gram. 174. 1817. 



Culms 2-4 tall, erect, simple, smooth and glabrous. 

 Sheaths longer than the internodes, crowded at the 

 base of the culm, woolly; ligule very short, minutely 

 ciliate; blades i long or more, about 2" wide, attenuate 

 into a long slender point, smooth beneath, scabrous 

 above; panicle i-2 long, strict, branches erect or occa- 

 sionally somewhat spreading ; outer scales of the spike- 

 let awn-pointed, the first $"-7" long, exceeding the 

 second ; third scale slightly shorter than the second, 

 middle awn 8"-i2" long, usually horizontal, the lateral 

 awns about two-thirds as long, erect or divergent. 



Dry sandy soil. Delaware to Florida. Oklahoma and 

 Texas. Aug.-Sept. 



