26 CONTRIBUTIONS FROM THE NATIONAL HERBARIUM. 



species. The Oaxaca specimen is regarded as the type, as this is the one in 

 the Steudel Herbarium. 



Panicum lanatum, sorghoideum Griseb. Fl. Brit. W. Ind. 551. 1864. Based 

 on Panicum sorghoideum Desv. 



Panicum martinicense Griseb. Fl. Brit. W. Ind. 552. 1864. " Jamaica ! 

 Wullschl.; [Martinique!, Panama!, Guiana]." Because of the specific name 

 the plant from Martinique is taken as the type. This is the specimen men- 

 tioned earlier in the description, "P. fuscum, Sieb. Mart. 29." 



Panicum swartzianum Hitchc. Contr. U. S. Nat. Herb. 12: 140. 1908. Based 

 on P. lanatum Swartz, not P. lanatum Rottb. 



Lasiacis swartziana Hitchc. Bot. Gaz. 51: 302. 1911. Based on Panicum 

 sicartzianum Hitchc. 



Lasiacis sorghoidea Hitchc. & Chase, Contr. U. S. Nat. Herb. 18: 338. 1917. 

 Based on Panicum sorghoideum Desv. 



DESCRIPTION. 



Culms much branched, erect or clambering to a height of 5 to 7 meters, the 

 strong central cane as much as 1 cm. thick, glabrous or pubescent, the main 

 branches sometimes 1 meter long or more, arcuate, bearing slender branchlets 

 toward the pendent ends, or the branchlets fascicled on the main culm, the 

 young shoots usually pubescent ; sheaths pubescent, especially on the margin 

 and collar, the surface sometimes glabrate ; ligule inconspicuous ; blades lance- 

 olate or elliptic-lanceolate, those of the main culm or of vigorous shoots as much 

 as 20 cm. long and 3 cm. wide, those of the fertile branches usually 8 to 12 cm. 

 long and 1.5 cm. wide, or on the fascicled branchlets smaller, often falcate, 

 velvety on both surfaces or only puberulent or glabrate above ; panicles on the 

 main culm and larger branches usually 10 to 20 cm. long, at maturity as wide or 

 wider, rather compactly many-flowered, the branches long and again branched, 

 the axes very scabrous ; spikelets 4 to 5 mm. long. 



The specimens cited vary in the amount of pubescence, but all are at least 

 puberulent on the under surface of the blades. In some the young shoots are 

 conspicuously villous or velvety-pubescent ; in others they are glabrous. Possibly 

 these represent distinct species. In general the main or primary panicles are 

 large, and rather open with ascending branches. Extended field study of this 

 complex group is necessary before it can be satisfactorily elaborated. 



DISTRIBUTION. 



Ravines, hedges, and borders of woods throughout tropical America. 



San Luis PoTosf: Las Canoas, Pringle 3808. 



Jalisco: Guadalajara, Hitchcock 7348. San Nicolas, Hitchcock 7207. 



Guanajuato: Duge's in 1897. 



Michoacan : Morelia, Arsdne in 1909. 



Veracruz: Zacuapan, Purpus 3779, 6206. Mirador, Mohr in 1857; Ross 613; 

 Liebmann 296, 300. Tlapacoyo, Liebmann 293. Misantla, Liebmann 289. 

 Orizaba, Smith 581 ; Bourgeau 2648 ; Hitchcock 6389. Jalapa, Hitchcock 

 6542, 6674, 6680 ; Rose 6144. Cordoba, Bourgeau " 1459 and 1936 " ; Fink 

 in 1893 ; Seaton 393 ; Hitchcock 6442, 6455, 6458. Colipa, Liebmann 290. 



Morelos: Cuernavaca, Ross 254; Pringle 5960, 6663; Hitchcock 6824. 



Oaxaca : Tomellin Canyon, Pringle 6701. Tuxtepec, Nelson 372. Trapiche 

 de la Concepcion, Liebmann 284. San Pablo Huitzo, Conzatti 2012. 



