POACEAE. 31 



1. Aristida adscensionis L. Sp. PI. 82. 1753. 



Aristida stricta Griseb. Fl. Brit. W. I. 534. 1864. Not Michx. 1803. 



Annual, tufted, glabrous; culms slender, erect, or ascending, 3-7 dm. 

 long, branching from the lower nodes. Leaf -blades thin, flat or involute; 

 panicles narrow, 1.5 dm. long or less, with short appressed branches or the 

 lower branches spreading; awns about equal in length, 12-20 mm. long. 



In sandy places and in the scrub, Great Exuma. Long Island, Fortune Island, 

 Crooked Island, Grand Turk, Caicos Islands, and Inagua : West Indies ; Ascen- 

 sion Island ; continental tropical America. ANNUAL TRIPLE-AWNED GRASS. 



2. Aristida cognata Triu. & Eupr. Mem. Acad. St. Petersb. VI. Sci. Nat. 5*: 



127. 1842. 



Perennial ; culms slender, tufted, spreading, 3-6 dm. tall. Leaves invo- 

 lute-filiform, the upper shorter; panicle spike-like, strict, or the top some- 

 times nodding, its short branches ascending ; awns 1-2 cm. long, horizontal 

 when old, nearly equal in length. 



Roadside, Long Cay : Jamaica ; Porto Rico ; St. Thomas ; St. Croix. PERENNIAL 

 THIPLE-AWNED GRASS. 



3. Aristida gyrans Chapm. Bot. Gaz. 3: 18. 1878. 



Perennial; culms tufted, wiry, erect, 3-7.5 dm. tall, usually simple, or 

 little branched. Leaves 3-5 cm. long, about 1 mm. wide, flat, or becoming in- 

 volute in drying; spike-like panicles 0.5-1.5 dm. long, strict, or sometimes 

 nodding, the few short branches appressed; outer scales of spikelet awn-pointed, 

 the third scale from two-thirds to three-quarters as long as the first, middle 

 awn 1-1.5 cm. long, horizontal, the lateral awns somewhat shorter, erect or 

 divergent. 



White-lands and palmetto-lands, New Providence : Florida ; Cuba ; Hispaniola. 

 Recorded by Small in Miami Flora as A. purpurascens Poir., which it resembles. 

 FLORIDA TRIPLE-AWNED GRASS. 



4. Aristida scabra (H.B.K.) Kunth, Eev. Gram. 1: 62. 1829. 



Streptachne scabra H.B.K. Nov. Gen. 1: 124. 1815. 



Streptachne cubensis A. Bich. in Sagra, Hist. Cub. 11: 311. 1850. 



Perennial ; culms 1 m. high or less, erect, simple. Leaves involute, at least 

 when dry, 2-3 dm. long, about 1 mm. thick; panicle 2-3 dm. long, its branches 

 ascending, the longer ones up to 14 cm. long; spikelets short-stalked; terminal 

 awn about 2 cm. long, the lateral ones minute. 



Pine and scrub-lands. Great Sturrup Cay, Andros, New Providence, Eleuthera, 

 Cat Island, Cave Cay, Rum Cay, Watling's Island, Acklin's Island, Crooked Island, 

 Fortune Island, Mai-iguana and Inagua : Cuba ; Mexico. Referred by Dolley to 

 Stipa sp. Ortaclme floridana (Chapm.) Nash may not be distinct from this. TALL 

 TRIPLE-AWNED GRA_SS. 



20. MUHLENBERGIA Schreb. ; Gmel. Syst. Nat. 2: 171. 1791. 



Mostly perennial grasses, with flat or convolute leaves and paniculate in- 

 florescence. Eootstocks often scaly. Spikelets 1-flowered, very rarely 2-flow- 

 ered. Scales 3, very rarely 4; the outer ones empty, membranous or hyaline, 

 acute and sometimes awned; third scale 3-5-nerved, subtending a palet and 

 perfect flower, obtuse, acute, or very often produced into a capillary awn ; palet 

 2-keeled. Stamens often 3. Styles distinct. Stigmas plumose. Callus minute. 

 Grain narrow, free, tightly enclosed in the scale. [In honor of Henry Muhlen- 

 berg, 1756-1817, North American botanist.] About 60 species, chiefly natives 

 of America, a few Asiatic. Type species: Mulilenbergia Schreberi Gmel. 



