HITCHCOCK AND CHASE NORTH AMERICAN PANICUM. 



37 



DESCRIPTION. 



Plants spreading, ttsually prostrate, or with a decumbent base, rooting at the lower 

 nodes; culms slender, usually freely branching, ascending 10 to 30 cm. above the 

 decumbent or creeping base, glabrous, the nodes usually puberulent; sheaths 



loose, glabrous, densely ciliate, shorter than the inter- 

 nodes; ligule a dense ring of hairs 1 mm. long or less; 

 blades lanceolate or ovate-lanceolate, 1.5 to 6 cm. long, 

 4 to 12 mm. wide, cordate, glabrous or puberulent on 

 both surfaces, the white, undulate margin hispid- 

 scabrous, ciliate at base with long, stiff hairs; inflores- 

 cence finally long-exserted,. 2 to 6 cm. long, consist- 

 ing of 3 to 12 spike-like, ascending or spreading racemes 

 arranged along a main axis; racemes solitary or some- 

 times somewhat fascicled, the upper* approximate and 

 shorter, the lower rather distant and 2 or 3 cm. long; rachises and pedicels scabrous 

 and usually sparsely pilose with long, weak hairs; spikelets borne on one side of the 

 rachis, irregularly and rather densely clustered, on pubescent pedicels 1 mm. or less 

 in length, elliptic, 1.9 to 2 mm. long, 0.9 to 1 mm. wide, acute, glabrous; first glume 

 about one-sixth the length of the spikelet, rounded or truncate; second glume and 

 sterile lemma slightly exceeding the fruit, strongly 5 to 7-nerved; fruit 1.7 mm. long, 

 0.8 mm. wide, elliptic, apiculate. 



As a whole this species is very uniform, but the long hairs on the secondary rachises 

 and pedicels are sometimes wanting. 



Fig. 17.— P. reptans. From type 

 specimen of P. prostratum Lam. 



DISTRIBUTION. - 



Moist open ground and a frequent weed in waste places and cultivated soil, Florida 

 to Texas, Mexico, and the West Indies, south to northern South America; also in the 

 tropical regions of the Eastern Hemi- 

 sphere. 



Florida: Apalachicola, Biltmore 

 Distr. Chapman Herb. 4276 

 (Gray Herb.). 



Alabama: Mobile, Mohr in 1884 . 



Louisiana: Pointe a la Hache, 

 Langlois 45 in 1882, 154 in 

 1883; Burnside, Combs 1431; 

 New Orleans, Ridell in 1840; 

 Algiers, Tracy 1837. 



Texas: Columbia, Bush 266, 1296; 

 Industry, Wurzlow 6; Houston, 

 Thurow 21 in 1903; Pierce, Tracy 7387; Lynchburg, Joor 39 in 1884; without 

 locality, Nealley in 1*884 and 1888. 



Mexico: Cuicatlan, Nelson 1622. 



Cuba: Habana, Curtiss 691, Hitchcock 146, Leon 276, 292, 297, 566, 576, 906, 910c; 

 Madruga, Curtiss 536; San Antonio, Hitchcock 145; Herradura, Tracy 9103; 

 Cienfuegos, Pringle 73; Baracoa, Pollard, Palmer & Palmer 19; La Magdalena, 

 Earle & Baker 2455; Santiago, Leon 910; Guayabal, Leon 910b; without local- 

 ity, Wright 3857. 



Jamaica: Hope, Harris 6845; Gordon Town, Hart 838. 



Porto Rico: Guanica, Millspaugh PI. Utow. 726, Sintenis 3368; Salinas de Cabo, 

 Sintenis 847; Coamo Springs, Goll 662; Ponce, Heller 497. 



Danish West Indies: St. Croix, Ricksecker 77; St. Thomas, Eggers 293 (Hitch- 

 cock Herb.). 



Fig. 18.— Distribution of P. reptans. 



