HITCHCOCK AKD CHASE — NOETH AMEHICAN PANICUM. 



137 



Fig. 131.— p. millegrana. From type 

 specimen of P. rugulosum Trin. 



Panicum rugulosum subvelutinum Doell in Mart. Fl. Bras. 2^: 259. 1877. "A d. 

 Wullschlaegel {n. 1612) in Surinamiae districtu Paraensi lecta." We have not seen 

 this specimen but the description, "foliorum lamina utrinque sub velutina, " would 

 indicate the form with velvety blades. 



DESCRIPTION. 



Plants perennial, spreading; culms sparingly branching, 0.5 to 1 meter high, 

 ascending from a decumbent base, softly pubescent to glabrous; sheaths ciliate and 

 with a dense ring of pubescence at the summit, otherwise papillose-pilose to glabrous; 

 ligules membranaceous, scarcely 0.3 mm. long; blades ascending or spreading, thin, 

 ovate-lanceolate, 4 to 15 cm. long, 10 to 30 mm. wide, somewhat unsymmetrical at 



the rounded or slightly cordate, sometimes ciliate, 

 base, softly pubescent, or sometimes velvety, on 

 both surfaces to glabrate except near the margin 

 and at the base; panicles short-exserted, finally 

 loose and rather few-flowered, 10 to 20 cm. long, 

 about two-thirds as wide when expanded, the 

 rather few, slender, branches stiffly ascending or 

 spreading, bearing toward the ends short, ap- 

 pressed branchlets with 1 to 3 rather short-pedi- 

 celed spikelets; spikelets 2 to 2.3 mm. long, 1 to 

 1.2 mm. wide, obovate, obtuse, turgid, at maturity 

 olivaceous or brown, glabrous or inore commonly papillose-hispidulous; first glume 

 about two-thirds as long as the spikelet, acute; second glume slightly shorter than 

 the sterile lemma, exposing the summit of the fruit at maturity, both 5-nerved, in 

 glabrous spikelets the nerves bordered by interrupted rows of minute papillae; fruit 

 1.9 to 2.1 mm. long, about 1 mm. wide, elliptic, obscurely pointed, papillose-rough- 

 ened, becoming dark brown at maturity. 



This species as here defined is very variable. The examination of a greater num- 

 ber of specimens and field study may show I\sellowii to be distinct from P. millegrana. 

 From the material at hand they can not be satisfactorily separated, for while most of 

 the specimens have either glabrous or papillose-hispidulous spikelets a few have 

 both sorts in the same panicle, and the pubescence of the sheaths and blades can not 

 be correlated with that of the spikelets. 



The following specimens have glabrous spikelets: Fendler 1641, Heyde & Lux 

 3927, Eolway 3083, Liebmann PI. Mex. 275, Lofgren 1228, Regnell III 1359**, Riedel/ 

 Rushy 233, Smith 2146, Widgren in 1844. 



In Spruce 603 and Tucrckheim 657 most of the spikelets are glabrous but some in the 

 same panicle are hispidulous, while in Wright 3455 the greater number of the spikelets 

 are hispidulous but glabrous ones are found in the same panicle. 



DISTRIBUTION. 



Damp woods, Mexico and Cuba, south to Brazil. 

 Mexico: Mirador, Liebmann 275; Jalapa, Eolway 3083; State of Chiapas, 



Heyde & Lux 3927. 

 Guatemala: Dept. Alta Vera Paz, Tuerchheim 657, 8783, 8784. 

 Costa Rica: El General, Pittier 10615. 

 Cuba: Habana, Wright 3462 in part; La Catalina, Wright 3455; Pinar del Rio, 



Wright 3855; Herradura, Hitchcock 180, Tracy 9098. 

 Colombia: Santa Marta, -Smii/j 2146. 

 Venezuela: Tovar, Fendler 1641. 

 Brazil: Campinas, Novaes 1249; Sao Paulo, Lofgren 1228; Rio Janeiro, Widgren 



in 1844; Prov. Minas Geraes, Regnell III 1359**; Santarem, Sp,ruce 603; 



Madeira, Rusby 233; without locality, Burchell 4146, 4315-2, 4653, Riedel. 

 Paraguay: Laguna Ipacarary, Fiebrig 561 (Field Mus. Herb.). 



