HITCHCOCK AND CHASE GRASSES OF THE WEST INDIES. 365 



Culms erect or ascending; spikeletB sometimes approxi- 

 mate but not crowded. 

 Culms rigid and wiry, bearing fascicled branches; 

 leaves commonly in pairs, the blades usually 



short and rigid 3. A. curtifolia. 



Culms not rigid, simple or sparingly branching, the 

 branches not fascicled. 

 Blades involute-setaceous, commonly clustered at 



the base 4. A. refracta. 



Blades flat, about 1 mm. wide, with a thick car- 

 tilaginous marginal band 5. A. gyrans. 



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



Arisfida humilis H. B. K. Nov. Gen. & Sp. 1: 121. 1816. 



Aristida bromoides H. B. K. Nov. Gen. & Sp. 1 : 122. 1816. 



Aristida maritima Steud. Syn. PI. Glum. 1 : 137. 1854. 



A densely tufted glabrous annual, the slender wiry culms ascending or erect 

 from a geniculate base, freely branching from the lower nodes, the narrow 

 blades commonly involute, the nodding panicles about 10 to 15 cm. long, the 

 slender branches short, appressed, or sometimes the lower 5 cm. or more long, 

 spreading and flexuous, the spikelets short-pediceled, mostly clustered, the equal 

 awns 12 to 20 cm. long. Extremely variable in appearance, ranging from dwarf 

 plants with narrow compact panicles to larger plants, as much as 70 cm. tall, 

 with flexuous panicles. 



Open dry ground and waste places, throughout the warmer parts of America 

 and the Old World. Originally described from the island of Ascencion. 

 Aristida humilis was described from Cumana, Venezuela; Aristida bromoides 

 from Ecuador, and Aristida maritima from Guadeloupe. This species has been 

 commonly referred to A. dispersa Trln. & Rupr.* and Is one of the forms the 

 authors unite under this name. Grisebach* refers this species to A. itricta 

 Michx. 



Bahamas (Crooked Island, Long Cay, Long Island), Jamaica (In the vicinity 

 of Kingston), Haiti, Santo Domingo, Porto Rico (along the southwestern coast 

 and on Mona Island), St. Croix, St. Jan, Antigua, Montserrat, and Guadeloupe. 



2. Aristida cognata Trin. & Rupr. M6m. Acad. St. P6tersb. VI. Sci. Nat. 5': 127. 



1842. 



Aristida swartziana Steud. Syn. PI. Glum. 1: 137. 1854. 



Culms tufted, slender, wiry, spreading, 15 to 30 cm. long, branching from the 

 lower nodes; blades flat or Involute, flexuous, densely scabrous and sparsely 

 long-vlllous on the upper surface; panicles narrow, the short branches ascend- 

 ing, the spikelets clustered. Resembling short-awned specimens of A. adscen- 

 sionis but usually taller and distinguishable by the perennial base. 



Stony ground, southern Jamaica, Porto Rico (Boqueron), St. Thomas, whence 

 originally described, and St. Croix. Aristida swartzixina was described from 

 Jamaica. Grlsebach * refers this species to A. purpurascens Polr. 



3. Aristida curtifolia Hltchc. Contr. U. S. Nat. Herb. 12: 235. 1909. 



Culms densely tufted, wiry, rigid, 30 to 50 cm. tall, with fascicled branches; 

 alternate internodes commonly shortened, bringing the leaves together in pairs, 

 the blades Involute, rigid, mostly short and spreading; panicles few-flowered, 

 3 to 10 cm. long, the awns about 12 mm. long. 



'M6m. Acad. St. P6tersb. VI. Scl. Nat. 5': 129. 1842. 

 " Fl. Brit. W. Ind. 534. 1864. 



