HITCHCOCK AND CHASE—TROPICAL NORTH AMERICAN PANICUM. 529 
DISTRIBUTION. UI 
Swamps, growing in the water, south- 
ern Mexico to Panama. 
Tapsasco: Between San Juan Bau- orn, 
tista and San _ Sebastian, ? 
Rovirosa 625. - of | 
GUATEMALA: Puerto Barrios, Hitch- 
cock 9153. _ 
Panama: Frijoles, Hitchcock 8388. Fa. 142.—Distribution of P. stagnatile. 
113. Panicum grande sp. nov. 
Plants perennial, gregarious, producing extensively creeping or floating leafy 
stolons about 5 mm. thick; culms 1.5 to 2 meters or more high, erect from a long decum- 
bent base with papery sheaths and tufts of fibrous roots, 1 to 2 cm. thick, simple or 
sparingly branching,. succulent, the nodes densely appressed-hirsute; sheaths over- 
lapping except toward the summit, glabrous, the junction with the blade in drying 
presenting a darkened triangle on each side; ligule membranaceous, about 2 mm. long; 
blades flat, as much as 1 meter long and 6 cm. wide (the upper and lower smaller), at 
base narrower than the sheath, gradually widening to about the middle, narrowing 
rather abruptly to the acuminate apex, glabrous, striate, somewhat plicate, the 
margins strongly serrulate; panicle as much as 60 cm. long and 40 cm. wide, the axis 
and branches strongly several-angled, scaberulous, the promi- 
nent pulvilli minutely pubescent, the branches stiffly 
spreading, naked at base, the lower in whorls, the short 
ultimate branchlets and the pedicels appressed along the 
rather loose secondary branchlets, the pedicels mostly 1 to 
2 mm. long; spikelets 2.5 mm. long, 0.9 mm. wide, nearly 
terete, pointed, glabrous; first glume slightly over half the 
length of the spikelet, the second glume and sterile lemma 
equal, exceeding the fruit, somewhat beaked beyond it; 
fruit 1.8 mm. long, 0.7 mm. wide, narrowly obovate, smooth 
and shining, the lemma and palea indurate but the lemma 
margins flat. 
Type in U. 8. National Herbarium, nos. 693329, 693330, 693331 (parts of the same 
individual), collected in the water of a swamp along the margin of Gatun Lake, Canal 
Zone, Panama, December 15, 1911, by A. 8. Hitchcock (no. 9178). 
This species grows in large masses in swamps, flowering in December. The broad 
blades give a lily-like aspect to the plants earlier in the season. In Gatun Lake, 
Panama, plants were found growing in 10 feet of water. 
Doell! describes this species under the name Panicum multiflorum Poir.,? but the 
latter name applies to a different species.* Panicum grande is allied to the South 
American P. grumosum Nees, P. rivulare Trin., and P. prionitis Nees, from all of which 
it differs in its aquatic habit and open panicle and in the more indurate fertile lemma 
and palea; from P. rivulare and P. prionitis in the equal second glume and fertile 
lemma. 
Fic. 143.—P. grande. From 
type specimen. 
1 Mart. Fl. Bras. 27: 215. 1877. 
2 Encycl. 4: 282. 1816. 
3 See Contr. U. 8. Nat. Herb. 15: 48. 1910. 
82472°—15——_6 
