780 Oedbb 156.— GEAMINB^. 



3 A. gracilis BU. Culm very slender, a foot or more high ; Ivs. eetaoeous, scarce 

 1" wide, erect, with short sheaths, pilous at the throat ; panicle very slender; 

 apikelets somewhat remote, appressed; lateral awns short (6 to 7"), erect, inierme- 

 d'.ate one longer (10 to 12"), spreading- — U Sandy places, Mass. to Ga., W. to 111. 

 A grass of httle value, as well as the other species of this genua. 



4 A. lan&ta Poir. Culm erect, 2 to 4f, hairy and branched below ; Ivs. linear, 

 flat. If long, 2 to 3" wide, hairy, especially on the upper surface; sheailis longer 

 ihan tlie joints, clothed with a woolly tomenium ; branches of the erect, contracted 

 panicle, tomentous at base ; glumes unequal, longer than {he pales ; awns about 

 equal, spreadmg, as long as the pale (4 to 6"), the middle rather longest. — li In 

 poor, sandy soi£, S. States. Sept, Oct. (A. lanosa EU.) 



5 A. spioiformis BU. Culm 1 to 3f high, simple ; Ivs. and sheaths glabrous, the 

 latter shorter than the joints ; panicle dense-flowered, spilce-like and cylindrical ; 

 glumes much shorter than the flower, both awned; middle awn of the flower long- 

 est, villous at the base, all three about as long as the pale. — y Wet pine barrens, 

 S. Car. to Fla. Sept., Oct. 



6 A. purpurdscens Poir. Culm erect, simple, filiform, 2 — 3f; Ivs. very narrow, 

 flat, erect, a foot in length, with short, open sheaths ; panicle long, loosely spicate ; 

 spikelets on short, clavate, appressed pedicels ; gls. iio 5" long, purplish ; awns V 

 long, nearly equal, divaricate, twice the length of the glabrous pale. — 1( Sandy 

 woods. Northern States. Sept. (A. affinis Kunth. A. raeemosa Muhl.) 



7 A. stricta Mx. Upeight Aeistida. Culm strictly erect, caespitous, branched, 

 1 — 3f; Ivs. straight, erect, pubescent, linear, convolute above; panicle long, 

 loosely racemous ; spikelets appressed ; gls.{3 to 5" long) unequal, very acute, lower 

 pales hairy at base ; awna twice as long as the pales, spreading, the middle one 

 the longest. — y Penn. to Fla. (Chapman), W. to Mich. 



8 A. oligdntha Ms. Culms erect, sparingly branched, 1 2 to 20' nigh ; pan. ra- 

 ceme-like, remotely few-flowered ; gls. short awned, equaling the pale (J'), which 

 bears 3 divaricate awns thrice its own length, the middle one some longer ; Ivs. 

 involute setaceous. — 2f Prairies, 111. to Ark. and Va. 



9 A. tuberouldsa Nutt. Culm erect (declinate at base), 8 — 20', rigid, with 

 small tubercles in the axils of the numerous brauehea ; nodea tumid ; Ivs. long and 

 narrow-linear; pan. largo, loose, simple; spikelets pedicellate; gls. nearly 1' long, 

 linear, awned; upper paleae involute, the awns 2' long, hiapid upwards, twisted 

 together to near the middle, thence finally horizontally divaricate. — If A very sin- 

 gular species, in dry prairies, 111., Wis. to Ky., Tenn., also found in N. J. 



13. STIPA, L. Weather Grass. (Lat. stipa, a foot-stalk ; allud- 

 ing to the stipitate fruit.) Spikelets l-flowerod, the flower deciduous, 

 ■with its thick, bearded, pointed stipe ; glumes membranous ; pales cori- 

 aceous, shorter than the glumes, the lower with a long, twisted or bent 

 awn, jointed at the apex ; caryopsis striate ; stamens 3 ; stigma plum- 

 ous. — 71 Fls. paniculate. Lvs. very narrow. The long awns are deli- 

 cately hygrometric twisting or untwisting according to the state of the 

 atmosphere. 



1 S. aven^cea L. Black Oat Grass. Culm naked above, 2 — 3f ; lvs. smooth, 

 striate, setaceous, chiefly radical ; panicle spreading, somewhat 1 -sided, 4 — 6' long, 

 at length diffuse, branches capillary, solitary and in pairs ; ghimes nearly equal, 

 mucronate, as long as the dark brovm, cylindric fruit; scales 2, lanceolate; awn 

 twisted below, bent above, 2 — 3' in length.— U. S. and Can. (S. Virginica Pers.) 



2 S. jlinoea Pursh. Culm 2 — 3f; lvs. convolute filiform, smooth inside, long; 

 pan. loose ; gls. loose, filiformly acuminated to more ihan twice the length of the fruit; 

 fr. attenuated at base into a stipe, which is a third of its length, stipe acute, pu- 

 bescent ; paleae obtuse, distinctly articulated to the awn, which is smooth and slen- 

 der, at length contorted and 4 — 6' in length, — y Prairies, 111., Mo. When in fruit 

 the pungent stipe adheres to everything that comes in its way. Aug. 



14. ORYZOP'SIS, Mx. Mountain Rice. (Gr. 6pv^a, rice, oipig, ap- 

 pearance.) Spikelets 1-flowered ; glumes membranous-bordered, veined, 



