Aristida. 



CLXI. GRAMINE^. 



8 9 



595 



Tribe 1. STIPACE^. — Infloresence panicled, Spikelets solitary, l-flo\ver- 

 ed. Glumes membranaceous. Paleae mostly two, lower one coriaceous, 

 involute, awned. 



1. ARISTlDA. 



Lat. arista, an awn ; characteristic of the genus. 



Panicle contracted or racemose ; glumes 2, unequal ; paleae pedi- 

 cellate, lower one with 3 long awns at the tip, upper one very minute 

 or obsolete. 



1. A. DicHOTOMA. Michx. Poverty Grass. 



Caespitose ; st. dichotomously branching ; pajiide contracted-racemose ; 

 lateral awns very short, the intermediate one nearly as long as the paleae, con- 

 torted. — A slender grass, in sandy soils, U. S., common. Stems 8 — 12' high, 

 branching at each joint. Leaves very narrow, with very short, open sheaths, 

 and a very short stipule. Spikelets slender, on clavate peduncles. Aug. 



2. A. PURPURASCENs. Poir. 



St. erect, simple, filiform, 2 — 3f high ; Ivs. very narrow, flat, erect, a loot 

 in length, with short, open sheaths ; 'panicle long, loosely spicate ; spikelets on 

 short, clavate, appressed pedicels; awns nearly equal, divaricate, twice the 

 length of the palese; palcce often dark purple.— 1[. Sandy woods, Northern 

 States. Sept. 



3. A. GRACILIS. Ell. 



St. very slender, a foot or more high ; Ivs. setaceous, erect, with short 

 sheaths, pilose at the throat ; panicle very slender ; spikelets somewhat remote, ap- 

 pressed ; lateral aiuns short, erect, intermediate one longer, spreading. -% Mass. 

 and S. States. A grass of little value, as well as the other species of tlds genus. 



4. A. TUBERCULOSA. Nutt. Lon^-awned Poverty Grass. 



St. erect (declinate at base), 8—20' high, rigid, with small tubercles in the 

 axils of the numerous branches ; nodes tumid ; Ivs. long and narrow-linear ; 

 panicle large, loose, simple ; spikelets pedicellate ; glumes nearly 1' long, linear, 

 awned ; upper palcce involute, the awns 2' long, hispid upwards, twisted together 

 to near the middle, thence finally horizontally divaricate.— '2]. A very singular 

 species, in dry pi'airies, 111., M'.ad! July, Aug. 



