HITCHCOCK AND CHASE NORTH AMERICAN PANICUM. 



179 



Fig. 176 



P. nudicaule. From 

 type specimen. 



Nudicaulia. — The following species does not seem to be closely allied with any other, 

 and hence is placed tentatively in a group by itself. So far as the technical 

 characters are concerned it might be placed in the group Dichotoma, but it 

 differs from any of the species of that group in the narrow, enveloping base of 

 the blades, and the nearly naked culms. When the autumnal form is known 

 the aflinity of the species may be shown. 



101. Panicum nudicaule Vasey. 



Panieum nudicaule Vasey, U.^S. Dept. Agr. Div. Bot. Bull. 8 : 31. 1889. "Swamps, 

 Santa Rosa County, Fla. (A. H. Curtiss.)" The type, in the National Herbarium, 



is the vernal form. It was collected in "Swamps, 

 Santa Rosa County, N. W. Florida," in May [1886] 

 by A. H. Curtiss (no. 3583*). 



DESCRIPTION. 



Vernal culms erect from a somewhat spreading 

 base, 40 to 60 cm. high, glabrous, the lower internodes 

 short, the two upper much elongated, thus producing 

 the effect of a long, nearly leafless stem; nodes gla- 

 brous, only the upper two visible; sheaths glabrous 

 or the overlapping basal ones sometimes sparsely 

 pubescent; ligules ciliate, less than 0.5 mm. long; 

 blades erect, rather thick, 4 to 10 cm. or some of the 

 lower as much as 13 cm. long, 5 to 8 mm. wide (the uppermost more or less reduced), 

 nearly linear, abruptly pointed, slightly narrowed and somewhat enveloping the 

 culm at base, glabrous; panicles long-exserted, 4 to 7 cm. long, hardly as wide, few- 

 flowered, the branches ascending; spikelets 2.7 to 2.9 mm. long, 1 to 1.2 mm. wide, 

 narrowly ovate, acuminate, glabrous; 

 first glume one-fourth to one-third as 

 long as the spikelet, usually pointed; 

 second glume and sterile lemma 7- 

 nerved, exceeding the fruit and pointed 

 beyond it; fruit 2 mm. long, 1 mm. 

 wide, elliptic, acute. 

 Autumnal form unknown. 



DISTRIBUTION. 



Swamps, western Florida and south- 

 em Alabama. 



Florida: Black water River 



Swamp, Santa Rosa County, Curtiss, B, 3583*. 

 Alabama: Gateswood, Tracy 84^1, 8432. 



Dichotoma. — Culms few to many in a tuft, glabrous, or the nodes only pubescent; 

 sheaths glabrous, or the lower sometimes pubescent, never conspicuously 

 hirsute; ligules ciliate, 0.7 mm. long or less; blades lanceolate, rarely as 

 much as 1 cm. wide, mostly glabrous; panicles usually open; spikelets 

 elliptical, not turgid (except in P. roanokense and P. caerulescens) , 1.5 to 2.5 

 mm. long; second glume and sterile lemma 5 to 7-nerved. Autumnal form 

 usually freely branching, erect, reclining, or prostrate, secondary leaves and 

 panicles much reduced. 



Fig. 177.— Distribution of P. nudicaule. 



