498 



CONTRIBUTIONS FROM THE NATIONAL HEEBARIUM. 



Porto Rico: Between Aibonito and Cayey, Chase 6341, Heller 522. Arecibo, 

 Chase 6440. Sierra Luquillo, Hioram 368, Chase 6713. Adjuntas Road, 

 fieZZer in 1902. Catano, -SeZZer 1378. JJtna.do, Britton & CovjellSM. Maysr 

 guez, Chase 6155, 6185, Sintenis 360. Along Rio Coamo, Chase 6549. Tru- 

 jillo Alto, Chase 6363, 6775. Jajome Alto, Cl-iase 6753. Santurce, dime 

 6354. Mount Morales, Britton & Marble 1068. Fajardo, Sintenis 1254. 



Danish West Indies: St. Thomas, Eggers 874 (K. U. Herb.). 



Leeward Islands: Antigua, Wullschlaegel 623. Guadeloupe, Dilss 3179. 

 Dominica, Jones 21, 25. 



Windward Islands: Martinique, Duss 535, 716 (K. U. Herb.). Barbados, Dash 

 450. St. Lucia, Voyage of the Albatross in 1887-88. Grenada, Broadway 1870, 

 3712, 4668. 



Trinidad: Port of Spain, Hitchcock 9984. Piarco Savanna, Hitchcock 10343, 

 10351, 10361. Brighton, Hitchcoch 10098. Pitch Lake, Hitchcock 10091. 

 Cumuto Station, Hitchcock 10068. Cedros, Hitchcock 10149, Bot. Gard. Herb. 

 2177, 2289. 



Tobago: Center of island, Hitchcock 10272. Spey Side, Hitchcock 10245. 



Venezuela: Llanos del Alto Apure, Jahn 201. 



Colombia: Cordoba, Pittier 521, 553. Calf, Pittier 665. Santa Alai-ta, Sraiih 

 202, 204. 



55. Panicum stevensianum sp. nov. 



description. 



Plants perennial, tufted, glabrous throughout; culms compressed, 30 to 60 cm. long, 

 spreading, prostrate, rooting at the nodes, the flowering ends and the branches ascend- 

 ing; sheaths loose, much shorter than the internodes, compressed, 

 keeled, ciliate on the overlapping margin; ligule a delicate mem- 

 brane aboutO.5 mm. long; blades fiat, rather firm, more or less spread- 

 ing, 4 to 10 cm. long, 5 to 10 mm. wide, tapering from a little above 

 the sparsely ciliate, truncate-cordate base to an acuminate apex; 

 panicles terminal on the culm and branches, short-exserted, 6 to 

 10 cm. long, narrow, consisting of several appressed or ascending 

 spikelike branches along an angled axis, the lower branches some- 

 what remote, 1.5 to 3 cm. long, usually longer than the internodes, 

 the upper approximate, all spikelet-b earing to the base, the short- 

 pediceled spikelets in crowded clusters, not secund, along a slender 

 scabrous rachis; spikelets about 2 mm. long and 0.8 mm. wide, acute, 

 somewhat inflated and gaping; first glume about one-fourth the length of the spikelet, 

 subacute, 3-nerved; second glume and sterile lemma equal, pointed, slightly exceed- 

 ing the fruit, 3 to 5-nerved, the lemma 

 inclosing a large palea and abortive 

 perfect flower; fruit 1.9 mm. long, 0.6 

 mm. mde, minutely scabrous at the 

 acute apex. 



Type in the U. S. National Herbar- 

 ium, no. 693323, collected "on wet 

 sand around pool, forming a dense car- 

 pet, white sand region, Campo Alegre 

 near Laguna del Tortuguero," Porto 

 Rico, November 25, 1913, by Agnes 

 Chase (no. 6616). 



This species appears to be most nearly related to the South American P. milioides 

 Nees, from which it differs in the short erect panicle branches, spikelet-bearing to 

 the base. 



Fig. 76.— p. ste- 

 vensianum. 

 From type 

 specimen. 



Fig. 77. — Distribution of P. stevensianum. 



