368 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



Creeping rhizomes wanting. 



Panicle large and diffuse, at least half the entire height of the plant. 



2. S. brasiliensis. 

 Panicle narrow, contracted or if somewhat open not diffuse, less than 

 one-third the entire height of the plant. 

 Glumes much shorter than the spikelet. 



Panicle branches slender, rather loosely arranged ; blades slen- 

 der and lax ; glumes about 0.3 mm. long, nearly equal. 



8. S. indicus. 



Panicle branches short, contiguous, forming a narrow, rather 



compact spike ; blades firm, as much as 5 mm. wide ; 



glumes 0.5 to 1 mm. long, unequal 9. S. berteroanus. 



Glumes unequal, the second as long as the spikelet. 

 Spikelets about 1.5 mm. long; panicle pyramidal. 



Lowermost panicle branches several in a whorl; sheaths 



hairy in the throat 3. S. argutus. 



Lowermost panicle branches in l's or 2's ; sheaths glabrous 



in the throat 4. S. atrovirens. 



Spikelets 2 to 4 mm. long; panicle elongate-oblong. 



Panicle green or whitish ; spikelets about 2 mm. long. 



5. S. domingensis. 

 Panicle purple; spikelets 2.5 to 4 mm. long. 



Basal sheaths copiously f elty-ciliate ; spikelets 3.5 to 4 



mm. long 11. S. cubensis. 



Basal sheaths not felty; spikelets 2.5 mm. long. 



10. S. purpurascens. 



1. Sporobolus muralis (Raddi). 



Agrosticula muralis Raddi, Agrost. Bras. 33. pi. 1. /. 2. 1823. 



A slender pale glabrous ascending annual, 30 to 70 cm. tall, with compressed 

 culms, fiat blades 2 to 3 mm. wide, and narrow, loosely flowered panicles about 

 half the entire length of the plant, the delicate branches ascending, the minute 

 spikelets long-pediceled. 



Waste ground, Lesser Antilles to Brazil. Originally described from Rio de 

 Janeiro. 



St. Croix, Tortola, Martinique, and St. Lucia. 



2. Sporobolus brasiliensis (Raddi) Hack. Bull. Herb. Boiss. II. 4': 278. 1904. 

 Aira brasiliensis Raddi, Agrost. Bras. 36. 1823. 



Eragrostis airoides Nees, Agrost. Bras. 509. 1829. 



Culms erect, commonly 1 meter tall, the long blades more or less involute, 

 scabrous on the. upper surface ; panicles rather more than half the entire length 

 of the plant, the numerous branches and branchlets subcapillary, flexuous, 

 ascending or spreading, the minute spikelets often 2-flowered. 



Savannas, Brazil; also in Cuba (Chirigote, Sumidero). Originally described 

 from Rio de Janeiro. Eragrostis airoides, based on a 2-flowered form, was 

 also described from Brazil. 



3. Sporobolus argutus (Nees) Kunth, Enum. PI. 1: 215. 1833. 



lAgrostis pyramidata Lam. Tabl. Encycl. 1 : 161. 1791, not Sporobolus pyrami- 



dalis Beauv. 1807. 

 ISporobolus affinis Kunth, Rev. Gram. 1: 68. 1829. 

 Vilfa arguta Nees, Agrost. Bras. 395. 1829. 

 Vilfa richardi Steud. Syn. PI. Glum. 1 : 153. 1854. 

 Agrostis pyramidalis A. Rich.; Steud. Syn. PI. Glum. 1: 153. 1854, as 



synonym. 



