HITCHCOCK AND CHASE—TROPICAL NORTH AMERICAN PANICUM. 475 
DISTRIBUTION. 
Wet places or in shallow water, margins of streams and ponds, mostly at low altitudes, 
Cuba, Porto Rico, and Mexico to Trinidad and Paraguay. 
Cotma: Alzada, Hitchcock 7067. 
GuatTEMALA: Puerto Barrios, Hitch- 
cock 9147. 
CusBa: Guanabacoa, Ledn 919. 
Ariguanabo, Ledén 1975, 1976. 
Habana, Leén 4155. El Cafio, 
Leén 1974. Laguna Jovero, 
Shafer 10912. Without local- 
ity, Wright 3456 in part, 3861. 
Porto Rico: Laguna del Tortu- Fig. 29.—Distribution of P. aquaticum. 
guero, Chase 6804. Lake Loisa, 
Chase 6778. Altode Bandera, Chase 6471. Utuado, Britton & Cowell 482. 
LEEWARD IsLtanps: Guadeloupe, Duss 3178 (K. U. Herb.). 
TRINIDAD: Pitch Lake, Hitchcock 10099. 
18. Panicum sucosum sp. nov. 
DESCRIPTION. 
Plants perennial, glabrous throughout except as noted; culms few to several in a 
tuft, 1 to 1.5 meters long, decumbent at base and rooting at the lower nodes, succulent; 
sheaths rather loose, about as long as the internodes; ligule a densely ciliate membrane 
about 1 mm. long; blades flat or somewhat involute in drying, 15 to 30 cm. long, 
3 to 9 mm. wide, linear, acuminate,. scaberulous on both surfaces, sparsely pilose 
above toward the base; panicle 15 to 30 cm. long, about 
half as wide, the axis and branches somewhat scabrous, 
the branches solitary or in pairs, rather stiffly spreading 
or finally horizontal, as much as 15 cm. long, naked at 
base for 1 or 2 cm., the internodes of the rachis mostly 3 
to 5 em. long, the branchlets appressed or ascending, 
mostly from the lower side; spikelets short-pediceled, 
somewhat appressed to the rachis, 3.3 to 3.7 mm. long, 
about 1 mm. wide, lanceolate, acuminate, glabrous; first 
glume one-fourth to nearly one-third the length of the 
spikelet, broadly triangular, usually subacute, 3-nerved; 
second glume and sterile lemma subequal, exceeding the 
fruit and pointed beyond it, 7 to 9-nerved; fruit about 
2.5 mm. long, 0.7 mm. wide, rather abruptly acuminate. 
Type in the U.S. National Herbarium, no. 693325, col- 
lected in water of a pond at Orozco, near Guadalajara, Jalisco, Mexico, September 29, 
1910, by A. S. Hitchcock (no. 7379). 
This species, which in the Revision ! was included in P. elephantipes, differs from 
P. dichotomiflorum in being perennial and in having larger spikelets; from P. aquati- 
cum in its larger panicle and more pointed spikelets and fruit; from P. elephantipes 
in having smaller, less succulent culms with narrower blades and in having less 
acuminate fruit. 
Fig. 30.—P. sucosum. From 
type specimen. 
1 Contr. U. 8. Nat. Herb. 15: 54. 1910. 
