ARisTiDA. TRIANDRTA. DIGYNIA. 81 



riaceous, involute, 3-awned at the tip ; superior valve 

 very minute or obsolete. Nectaries collateral. Gen. 

 pi. 125. Nutt. Gen. I. p. 57. Juss. p. 29. Roem. 

 &? Schult. Gen. 243. P. de Beaiiv. t. VIII. f. 5. 

 7. 10. Trin. Agrost. 46. Ch^etaria, Curtopo- 

 GON et Arthratherum p. de Beaiiv, Flowers 

 generally in contracted panicles. 



1. A. dichotoma Mich.: cespitose ; culm dichotomous ; 

 flowers racemose-spiked ; lateral awns very short, the inter- 

 mediate one contorted. Mich. FL I. p. 72. Pursh FL 



I. p. 72. Elliott Sk. I. p. 141. Muhl. Gram. p. 171. 

 CvKiovoGoa dichotomus P. de Beauv. Roem. ^ Schult, 



II. p. 398. 



Root annual or biennial, (perennial Ell.) Culms 8—12 inches 

 high, very slender, producing a short branch at every joint. 

 Leaves setaceous, erect, nearly smooth. Sheaths very short, 

 open. Flowers in racemes, on clavate peduncles. Calyx 

 shorter than the corolla ; glumes unequal, linear, mucronate, 

 serrulate on the keel. Corolla 1-valved, closely involute; la- 

 teral awns straight, not half thejength of the valve; middle 

 awn contorted or bent horizontally, (hygrometric) Stamens 3. 

 Styles 2. Seed linear, elongated. 



Hab. In sandy fields and in dry gravelly situations; sometimes 

 on hills ; common. September. 



2. A. stricta Mich.: culm and leaves straight, erect; 

 leaves pubescent ; raceme long, somewhat spiked, crowded, 

 awns twice as long as the corolla, spreading. M i c h. Ft. I. 

 p. 41. £//ioU SA;, I. p. 142. Pursh FL I. p. 72. 

 Muhl. Gram. p. 174. Ch^itaria stricta P. de Beauv. 

 Roem.^ Schult. II. p. 391. Arist. adscensionis Walt, 

 Car. p. 74. 



Root perennial. Culms cespitose, 2 — 3 feet high, branching at 

 the base. Leaves elongated, linear, convolute towards the 

 extremity. Flowers of the fianicle not crowded. Calyx: un- 

 equal, very acute. Inferior valve of the corolla hairy at the 

 base ; awns scabrous, the intermediate one the longest, but all 

 twice as long as the corolla. Elliott. 



Hab. Near Philadelphia. Mr. Collins. (Barton.) 



3. A. purpuras cens Poir.: culm filiform, erect, simple ; 

 leaves very narrow, flat; flowers in a long spiked panicle; 

 awns nearly equal, twice the length of the corolla, divaricate. 

 Poir. Enc. Supp. 1. p. 452. A. racemosa Muhl. Gram. 

 p. 1 72. Chjetaria purpurascens P, de B e a uv. Roe m, 

 ^ Schult, 11. p. 390. 



Root perennial. Culm 2 — 2\ feet high. Leaves about a foot 

 long, erect, very narrow, filiform towards the extremity, sea- 

 1! 



