HITCHCOCK AND CHASE — NORTH AMERICAN PANICUM. 163 



DISTRIBUTION. 



Low pine lands and hammocks, North Carolina to Florida and Louisiana. 



North Carolina: Onslow Count}-, Chase 3184; Roanoke Island, Chase 3214, 

 3226; New Hanover County, 

 Chase 4583, Hitchcock 1430, 

 1451, 1490, Kearney 250. 



South Carolina: Orangeburg, 

 Hitchcock 342, 1371. 



Florida: Baldwin, Combs 57, 

 Hitchcock 991, 993, 1000; Lake 

 City, Combs 100, 137, Hitch- 

 cock 1019, 1036; Madison, 

 Combs 288; Eustis, Nash 807. 



Alabama: Flomaton, Hitchcock 

 1040; Mobile, Kearney 24. 



Mississippi: Jackson County, Kear- 

 ney 283, Tracy 162; Biloxi, Chase 4360, Kearney 326 in part; Avondale, Tracy 

 4582. 



Louisiana: New Orleans, Drummond (Gray Herb.). 



89. Panicum polycaulon Nash. 



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. 



Fig. 151.— Distribution of P. ciliati 



DESCRIPTION. 



Vernal form similar to that of P. ciliatum, 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 2 mm. 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 coordinated 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 cilise. The following specimens have spikelets nearly or quite 2 mm. long: Flor- 

 ida: Kalamazoo, Hitchcock 763, Lakeland, Hitchcock 836; Dunedin, Tracy 6698. 

 Mississippi: Mississippi City, Hitchcock 1101. 



Fig. 152.— P. polycaulon. 

 From type specimen. 



