780 . Order 156.— GRAMINE^J. 



3 A. gracilis Ell. Culm very slender, a foot or more high ; lvs. setaceous, scarce 

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

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

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

 A grass of little value, as well as the other species of this genus. 



4 A. lanata 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; sheaths longer- 

 than the joints, clothed with a woolly tomentum ; branches of the erect, contracted 

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

 equal, spreading, as long as the pale (4 to 6"), the middle rather longest. — 2£ In. 

 poor, sandy soils, S. States. Sept., Oct. (A. lauosa Ell.) 



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

 latter shorter than the joints ; panicle dense-liowered, spike-like and cylindrical ; 

 glumes much shorter than the flower, both awaed; middle awn »f the flower long- 

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

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



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

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

 spikelets on short, clavate, appressed pedicels j. gls. 4 to 5" long, purplish; avjns V 

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

 woods, Northern States. Sept. (A. affinis Kunth. A. racemosa Muhl.) 



7 A. strfcta Ms. Upright Aristida. Culm strictly erect, ctespitous, .branched,. 

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

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

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

 tho longest. — If Penn. to Fla. (Chapman), W. to Mich. 



8 A. oligantha Mx. Culms erect, sparingly branched, 12 to 20' high; pan. ra- 

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

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

 involute setaceous. — % Prairies, 111. to Ark. and Va. 



9 A tuberculosa Nutt. Culm erect (decimate at base), 8 — 20 r , rigid,, with 

 small tubercles in the axils of the numerous branches ; nodes tumid ; Ivs. long and; 

 narrow-linear; pan. large, loose, simple ~ T spikelets pedicellate; gls. nearly 1' long,, 

 linear, awned; upper paleos involute, the awna 2' long, hispid upwards, twisted 

 together to near the middle, theneo finally horizontally divaricate. — 21 A very sin- 

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



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

 ing to the stipitate fruit.) Spikelets 1 -flowered, the flower deciduous, 

 with its thiok r 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 ; earyopsis- striate ; stamens 3 ; stigma plum- 

 ous. — 1C Fls. paniculate. Lvs. very narrow. The long, awns are deli- 

 cately hygrometric twisting or untwisting according to the state of tho 

 atmosphere. 



1 S. avenacea L. Black Oat Grass. Culm naked above, 2 — 3f ; Ivs. smooth, 

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

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

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

 twisted below, bent above, 2 — 3' in length. — TJ. S- and Can. (S. Virgiaica Pers.) 



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

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

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

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

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

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



i4. ORYZOP'SIS, Mx. Mountain Rice. (Gr. opv%a, rice, ox^tg, ap- 

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



