HITCHCOCK AND CHASE — NORTH AMERICAN PANICUM. 271 



162. Panicum breve 



B p. 



DESCRIPTION. 



Fig.301.— P. breve. From 

 type specimen. 



Vernal form purplish, culms in dense tufts, 5 to 17 cm. high, erect, stiff and wiry, 



glabrous or appressed-pubescent below; sheaths crowded at the base as in species of 



Festuca, those of the culms usually longer than the internodes, ciliate on the margin, 

 otherwise glabrous; ligules dense, about 0.3 mm. long; blades 

 firm, erect or ascending, 3 to 6 cm., sometimes 8 cm. long, 

 about 1.5 mm. wide when flattened out, strongly involute, 

 more or less falcate, sometimes strongly so, a few long, stiff 

 hairs on the margin toward the base, otherwise glabrous; panicle 

 short-exserted, 1.5 to 4 cm. long, nearly as wide, loosely flow- 

 ered, the flexuous branches spreading; spikelets 1.3 to 1.4 mm. 

 long, obovate, obtuse, turgid, puberulent; first glume one-third 

 to half as long as the spikelet; second glume and sterile lemma 



barely equaling the fruit at maturity; fruit 1.2 mm. long, elliptic. 



Autumnal form erect, branching from the middle nodes, the fascicled branches 



strict, the reduced wiry blades overtopping the panicles. 



Type U. S. National Herbarium no. 558435, collected April 5, 1906, in "low pine 



woods between scrub hills, among palmetto," Jensen, Florida, by A. S. Hitchcock 



(no. 734). 



This species is most closely related to P. glabrifolium., from which it is distinguished 



by its short, compact habit, by the 



strongly involute blades bearing long, 



stiff hairs near the base, and by the 



pubescent spikelets. 



DISTRIBUTION. 



Low pine woods and hammocks, east 

 coast of southern Florida. 



Florida: Indian River, Palmer 

 634 in 1874 in part; Jensen, 

 Hitchcock 734; Fort Lauder- 

 dale, Small & Carter in 

 1903; "About Boca Ratone Lake, below Delray," Small 6c Carter in 1903 

 (Biltmore Herb.). 



Fig. 302.— Distribution of P. breve. 



Lancearia. — Plants olive green, often purplish; vernal culms usually wiry, minutely 

 crisp-puberulent or glabrous; sheaths glabrous or puberulent, at least at the 

 summit; ligules nearly obsolete; blades glabrous or puberulent, usually 

 strongly ciliate, at least near the base; spikelets unsymmetrically pyriform, 

 that is, more swollen on the face than on the back; first glume thin and 

 shining, broad at the summit, obtuse or truncate ; second glume and sterile 

 lemma strongly 7 to 9-nerved, puberulent or glabrous. Species of the At- 

 lantic Coastal Plain. 



Spikelets 1.5 to 1.6 mm. long. 



163. P. pauciciliatum. 



Spikelets 2 mm. or more long. 



Blades, or some of them, at least 8 mm. wide; glabrous on 



the upper surface; fruit papillose-roughened 166. P. webberianum. 



Blades not over 6 mm. wide (or if wider, puberulent on 

 the upper surface) ; fruit smooth and shining. 

 Spikelets 2.4 to 2.6 mm. long; blades narrowed to- 



toward the base. T , 167. P. patentifolium . 



