133 TRIANDRIA. DIGYNIA. avena. 



lower part of the back, as long again as the valve, geniculate 

 about the middle; superior valve shorter, scabrous. Seed 

 linear-oblong. t^, , , , , • j 



Hab. In sandy fields. New-Jersey, near Philadelphia, and 

 throughout the pine-barrens. June. 



39 c. AIRA. L. 

 Calyx 2— 3-flowered, longer than the florets. Infe^ 

 rior valve of the corolla eroded or many-toothtd, awned 

 on die b-ick below the middle. Aira et Deschamp^ 

 siA P. de Beauv, t. XVIII. i. 4 et 5. Roem. ^ 

 Schult. Gen. 3i9 et 330. Deschampsia Trin. 

 Jgrost. 117. AiR^ spp. X., jYutt.y &c. Panicle 

 compfMind, generally spreading. Hair-grass. 



1. A. flfxuosa L. : panicle spreading, Irichotonnous ; 

 branches flexuous; calyx a little shorter than the florets, and 

 about the length of the awn; leaves setaceous; culnn nearly 

 naked. Wiild. Sptc.l.p.Sld. Eng. Bot. t. ]5\% Pursli 

 Ft. I. p. 377. M uhL Gram. p. 85. Elliott Sk. Up, 151. 

 Roem. ^ Schult. U. p. 678. 



Hoot perennial. Culm a foot and a half or two feet high. Leaves 



6 10 inches long, siiuated principally about the root. Panicle 



capillary, lax; loWcr branches somewhat verticillate ; the up- 

 per ones in pairs, G/wmes membranaceous, white, oblong- 

 lan( eolate, very acute, scabrous on the keel. Corolla hairy at 

 the base, unequal ; inferior valve shorter, 2-nerved, awned 

 from near the base, covered whh short appresscd hairs; awn 

 Kearlv as long aguin as the valve, geniculate ; superior valve 

 bifid at tie apf x. Slumens 3. 

 Hab. On rocky hills and in mountainous situations throughout 

 the northern States. June. 



2. A. cespitosa L. : panicle dilTuse ; florets about the 

 length of the cal):s ; awn short, straight ; leaves flat. W ill d. 

 Spec. I. p. 378. Purs h Fl. 1. p. 77. M u h L Gram. p. 85. 

 Desch \MrsiA ce.spilosa P. de B c auv. H o em. ^ S c kul i^ 

 11. p. 685. 



Root perennial. Culm cespitose, a foot and a half high. Leaves 

 very narrow, but flat, scabrous. Panicle capillary ; branches 

 somewhat verticillate, scabrous. Calyx smooth, of a bluish 

 colour, rarely 3-flowered ; inferior glume shorter and rather 

 obtuse. Corolla hairy at the base, with an awn at the base of 

 the inferior valve. 

 Hap- In swamps and bog-meadows. New-Jersey. Pennsyl- 

 vania and New-England. Muhlenberg. June. 



3. A. aristulata*: panicle capillary, spreading; branches 

 verticillate ami flexuous 5 calyx S-flowered, Ehorl(er than the 



