428 GRAMINACEiE. 



nearly leafless ; panicle racemose ; awn longer than the flower ; palt 

 whitish when mature. 



Rocky woods. Subarct. Amer. to N. Y. April, May. %. — Culm about 18 



inches high, simple, smoothish, purple at base. Radical leaves as long as the 

 culm, rough. Panicle very simple ; the branches short and appressed. 



White Mountain Rice. 



2. O. melanocarpa MuhL : culm leafy ; panicle nearly simple, the lower 

 branches more or leas spreading ; flowers somewhat racemose ; glumes 

 ovate-lanceolate ; paleae blackish when mature, somewhat hairy ; the lower 

 one with an awn 2 — 3 times as long as the flower. Piptatherum nigrum 

 Torr. Ft. 



Rocky woods. N, Eng. and N. Y. Aug. %.—Cvlm 2—3 feet high, erect, 

 simple. Leaves long, linear-lanceolate. Panicle sparingly branched. Avm 

 nearly an inch long. Caryopsis black. Black-fruited Mountain Rice. 



3. O. Canadensis Torr. : leaves very short, pungent ; panicle contracted, 

 the branches usually in pairs, ovoid ; paleae hairy ; awn short, often decidu- 

 ous or wanting. {Torr. N.Y. Fl.) Milium pungens Torr. Fl. 



Rocky hills. Mass. and N. Y. %. — Culm 8 — 15 inches high, slender, simple, 

 rigid. Radical leaves 6 — 8 inches long, about a line wide, at length involute, 

 pungent. Panicle oblong, few-flowered. Dwarf Oryzopsis. 



15. STIPA. Linn.—FedLtheT Grass. 



(From the Greek (ttvitt}, a feathery substance ; particularly applicable to one 

 of the species.) 



Spikelets 1 -flowered ; the flower stipitate. Glumes 2-valved, 

 membranaceous. Paleae 2, longer than the glumes, somewhat 

 coriaceous, cylindric-involute ; the lower awned at the summit. 

 Awn twisted at the base. Caryopsis terete, furrowed. — In- 

 florescence panicled. 



S. avenacea Linn. : leaves setaceous ; panicle spreading, somewhat se- 

 cund, the branches mostly in pairs; glumes as long as the paleae ; awn 

 very long, naked. S. barbaia Mich. 



Sandy woods. N. Y. and 3Iass. toGeor. June. Qi. — Culm about 2 feet high, 

 slender, simple. Leaves mostly radical, 6 — 8 inches long. Panicle nodding, at 

 length diffuse. Black Oat-grass. 



16. ARISTIDA. L«i?Mi.— Three-awned Grass. 

 (From the Latin arista, an awn or heard.) 



Flower stipitate. Glumes membranaceous, unequal. Paleae 

 mostly 2 ; lower one coriaceous, involute, 3 -awned at the tip ; 

 upper very minute or obsolete. Scales 2, entire, smooth. — 

 Spikelets racemose or paniculate. 



1. A. dichotoma Mich.: culm cespitose, dichotomously branched; panicle 

 contracted, racemose ; lateral awns very short ; the intermediate one nearly 

 as long as the palese, contorted. 



Sterile soils. Mass. and N. Y. to Car. Aug. (I) I— Culm 9—15 inches long, 

 slender, branching at the joints. Leaves flat, very slender, smoothish. Ra- 

 cemes on clavate peduncles. Forked Three-awned (xrass. 



