61 TRIANDRIA DIGYNIA 



florets single ; one with a dorsal awn, the other with an awn near the 

 base, Palex of the perfect floret 2, nearly equal, short, awnless. 

 Stame?i8 2. 



1. A. odotiatum, L. Panicle contracted into an oblong spike ; spike- 

 lets subpeduneulatc, pubescent. Bet k r, Hot. p. .402. Icon, Ell* Sk. 1, 

 tab. \. f. 1, (indifferent) Specim, Gray, Cram. I. no. 4 1. 

 Odorous Axthoxaxthum. Vulgo — Sweet-scented Vernal Grass, 

 Gallice — Flouvc odorante. Germanic*— Das Ruch gros. 



Root perennial. Culm erect, 12 to 18 inches high, rather slender. Leaves lin- 

 ear-lanceolate, shortish, striate, pubescent : sheaths nerved, sulcate ; ligule elon- 

 gated, membranaceous. Panicle contracted into an oblong, or ovoid-cyltndric 

 spike, becoming yellow when mature ; spike let 8 somewhat fascicled, on short pe- 

 duncles. Glumes very unequal, membranaceous, pubescent. Palea of \he perfect 

 floret very short, obtuse, nearly equal, smooth and shining, the lower one much 

 broader. Palaz of the lateral, or neuter florets, single, linear-oblong, ciliate en 

 the margins ; one of them with a geniculate aw n fr om near the base, inure than 

 twice as long as the palea ; the other with a straight awn, about as long as the pa- 

 lea, inserted OH the back near the summit. Stamens 2; anthers large. Stigmas 

 plumose, white. Seal oblong, blackish, shining. 



Ilab. Meadows, and borders of wood lands: common. Fl. May— June. /V.July. 



Obs. Introduced from Europe, and extensively naturalized. It. is remarkable 

 for having but 2 stamens —and for emitting a fra rant odor, when cut and partly 

 dry: But it is one of those grasses which rather belong to a thin soil,— and is not 

 considered very valuable, here. It is the only species of the genus which has 

 found its way to the U. States. 



§ 2. Atene.t: — Oat-grass Groupe. 



Sinkcletsfetr-floireraL Upper florets generally pecKcellate t and icith awn-liko 

 processes, or abortive rudiments, between the upper and lower ones. 



41. AIRA. L. .Vutt. Gen. 90. 

 [Greek, Aira, a deadly instrument ; originally applied lo a poisonous plant.] 



Spikelets 2-flowered ; the florets without an abortive rudiment between 

 them. Glumes 2, membranaceous and shining, a little unequal, about 

 as long as the florets. Pales nearly equal, pilose at base ; the lower 

 one lacerate or many toothed at apex, and awned on the back near the 

 base. 



1, A. flexuosa, L. Leaves setaceous, smooth ; panicle loose, spread- 

 ing, trichotomously branched ; branches smoothish, flexuose ; awns 

 geniculate, longer than the pale«. Beck-, JJot. p. 402. Sfkcim. Gray, 

 Gram. 1. no. 43, 



Flexuose Aira. 



Root perennial. Culm \ to 2 feet high, glabrous. Leaves principally radical, 

 or near the base of the culm, involute, setaceous, glabrous, 3 to 6 or 8 inches long; 

 she at lis deeply striate, somewhat scabrous; ligule oblong, truncate. Panicle ca- 

 pillary, lax, trichotomously branched; branches long, somewhat flexuose, nearly 

 smooth. Glumes membranaceous, white, oblong-lanceolate, very acute, about as 



