HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 163 
DISTRIBUTION. 
Low pine lands and hammocks, North Carolina to Florida and Louisiana. 
Norra Carona: Onslow County, Chase 3184; Roanoke Island, Chase 3214, 
3226; New Hanover County, 
Chase 4583, Hitchcock 1430, 
1451, 1490, Kearney 250. 
SoutH Carona: Orangeburg, 
Hitchcock 342, 1371. 
Fiorina: Baldwin, Combs 57, 
Hitchcock 991, 993, 1000; Lake 
City, Combs 100, 137, Hitch- 
cock 1019, 1036; Madison, 
Combs 288; Eustis, Nash 807. 
AtaBaMaA: Flomaton, Hitchcock 
1040; Mobile, Kearney 24. 
MississipPr: Jackson County, Kear- 
ney 283, Tracy 162; Biloxi, Chase 4360, Kearney 326 in part; Avondale, Tracy 
4582. 
Louisiana: New paece, Drummond (Gray Herb.). 
¥ TRHseEsx F°CUS 
89. Panicum polycaulon Nash. 
Fic. 151.—Distribution of P. ciliatum. 
Panicum polycaulon Nash, Bull. Torrey Club 24: 200.1897. ‘“‘Type specimen 
collected by the writer on August 20, 1895, in the flatwoods at Tampa, Florida, No. 
2420a.’’ The type, in Nash’s herbarium, consists of a spreading tuft of numerous 
culms, 10 to 17 cm. high, the overmature panicles nearly devoid of spikelets, and 
the first glume half the length of the spikelets, which are 1.6 mm. long. 
DESCRIPTION. 
Vernal form similar to that of P. ciliatwm, culms rarely over 20 cm. high, glabrous, 
but pilose in the long-exserted panicle; sheaths sparingly ciliate; blades on the 
average narrower than those of P. ciliatum; spikelets 1.5 to 1.6 mm. long (excep- 
tionally as much as 2 mm. long), 0.8 mm. wide, obovate, blunt, glabrous; first glume 
one-third to half the length of the spikelet, subacute; second glume and sterile lemma 
strongly nerved; fruit 1.4 mm. long, 0.8 mm. wide, elliptic, subacute, not umbonate. 
Autumnal form in flat, soft mats, similar to those of P. xalapense, but smaller. 
The type specimens of P. ciliatum and P. polycaulon differ in the spikelet char- 
acters, the former having pubescent spikelets 2 mm. long and the latter having gla- 
brous, more obovate, turgid spikelets 1.6 mm. long. Our 
numerous specimens, however, do not show these constant 
differences. Occasional specimens have glabrous spikelets 
as much as 2mm. long. A comparatively few specimens 
have pubescent spikelets that are of the smaller size. We 
have not found any distinct differences in habit that can 
be coérdinated with the spikelet characters. The range of 
the two forms is somewhat different, P. ciliatum extending 
from North Carolina to northern Florida, and P. polycaulon 
throughout Florida and southward into Cuba. It will be observed that the ranges of 
the two overlap in northern Florida and it is here that the intermediate specimens are 
found. A specimen from Tampa, Florida, Hitchcock 933, has blades nearly destitute 
of cilie. The following specimens have spikelets nearly or quite 2 mm. long: FLor- 
DA: Kalamazoo, Hitchcock 763; Lakeland, Hitchcock 836; Dunedin, Tracy 6698. 
Mississirri1: Mississippi City, Hitchcock 1101. 
Fie, 152.—P. polycaulon. 
From type specimen. 
