434 GRAMINE^. Aristida. 



16. ARISTIDA. Linn.; Kunth, enum. 1. p. 187. I'HREE-awned GRASS. 



[From arista, the Latin word for beard.] 



Flower slipitate. Glumes membranaceous, unequal. Paleje 2 ; the lower one terete-involute, 

 with a 3-parted or 3- cleft awn at the summit : upper palea very small, awnless. Ovary 

 stipitate, smooth. Scales 2, entire, smooth. — Leaves mostly involute. Spikelets racemose 

 or paniculate. 



1. Aristida dichotoma, Michx. (PI. cxlix.) Dichotomous Three-awned Grass. 



Culm cespitose, dichotomously branched from the base ; panicle contracted, racemose ; 

 lateral awn very short ; the intermediate one nearly as long as the paleas, contorted. — Michx. 

 fl. 1. p. 41 ; Pursh, Jl. 1. p. 72 ; Ell. sk. 1. p. 141 ; Ton: fl. \.p. 81 ; Bigel. fl. Bost. p. 

 31 ; Trin. diss. 1. p. 178 ; Beck, hot. p. 400; Darlingt. fl. Cest. p. 53; Kunth, enum. 1. 

 p. 188, and "gram. 2. t. 174." Curtopogon dichotomus, Beauv. p. 32. t. 8. /. 7. 



Annual. Culm 4-15 inches high, slender, branching at each joint. Leaves very slender, 

 ■ erect, smoothish ; the sheaths shut and open. Glumes unequal, linear, serrulate on the keel, 

 mucronate, or slightly awned a little below the tip. Paleas very unequal : lower one closely 

 involute, smoothish ; the lateral divisions of the awn not half the length of the palese ; the 

 middle one contorted, or bent horizontally. Stamens 3. Styles distinct. Caryopsis linear, 

 elongated. 



Sandy fields and dry sterile hill sides ; common. Fl. September. 



2. Aristida gracilis. Ell. Slender Three-aioned Grass. 

 Culm very slender, erect ; panicle spiked, the flowers appressed ; lateral awns rather 



shorter than the paleee, erect ; middle one longer, bent, not twisted ; lower palea spinulose on 

 the keel. — Ell. sk. 1. p. 142. t. 8. /. 3 ; Trin. diss. 1. p. 178 ; Kunth, enum. 1. p. 187. 

 A. stricla, Darlingt. fl. Cest. p. 53,. not oi Michx. 



Annual. Culm 4-15 inches high, smooth. Leaves very narrow, convolute when dry; 

 the sheaths with a few long hairs at the throat. Panicle 2-5 inches long, slender ; the 

 branchlets few-flowered and rather remote. Glumes a little unequal, somewhat awned, rough 

 on the keel. Lower palea rough, and the keel conspicuously serrulate-spinulose, a little 

 hairy at the base, often spotted or banded with dull purple or gray : lateral awns mostly 

 rather shorter than the paleag ; middle one more than twice as long as the others. 



Sandy fields, Suffolk county. Long Island. Fl. September. Tliis species is not uncommon 

 in the Pine barrens of New-Jersey. It never occurs except in the poorest lands. 



