HITCHCOCK AND CHASE—-NORTH AMERICAN PANICUM. 137 
Panicum rugulosum subvelutinum Doell in Mart. Fl. Bras. 2?: 259. 1877. ‘‘A el. 
Wullschlaegel (n. 1612) in Surinamiae districtu Paraénsi lecta.”” We have not seen 
this specimen but the description, ‘“‘foliorum lamina utrinque subvelutina,’’ 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 
1.2mm. wide, obovate, obtuse, turgid, at maturity 
olivaceous or brown, glabrous or more 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 
elabrous spikelets the nerves bordered by interrupted rows of minute papille; 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 P. sellowwi 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 & Luz 
3927, Holway 3083, Liebmann Pl. Mex. 275, Lofgren 1228, Regnell III 1359**, Riedel, : 
Rusby 233, Smith 2146, Widgren in 1844. 
In Spruce 603 and Tuerckheim 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. 
Fig. 131.—P. millegrana. From type 
specimen of P. rugulosum Trin. 
DISTRIBUTION. 
Damp woods, Mexico and Cuba, south to Brazil. 
Mexico: Mirador, Liebmann 275; Jalapa, Holway 3083; State of Chiapas, 
Heyde & Lux 3927. 
GUATEMALA: Dept. Alta Vera Paz, Tuerckheim 657, 8783, 8784. 
Costa Rica: El General, Pittier 10615. 
Cusa: Habana, Wright 3462 in part; La Catalina, Wright 3455; Pinar del Rio, 
Wright 3855; Herradura, Hitchcock 180, Tracy 9098. pal 
Cotomsra: Santa Marta, Smith 2146. 
VENEZUELA: Tovar, Fendler 1641. 
Braz: Campinas, Novaes 1249; Sao Paulo, Lofgren 1228; Rio Janeiro, Widgren 
in 1844; Prov. Minas Geraes, Regnell III 1359**; Santarem, Spruce 603; 
Madeira, Rusby 233; without locality, Burchell 4146, 4315-2, 4653, Riedel. 
Paraauay: Laguna Ipacarary, Piebrig 561 (Field Mus. Herb.). | 
