HITCHCOCK AND CHASE — NORTH AMERICAN PANICUM. 



155 



84. Panicum linearifolium Scribn. 



Panicum linearifolium Scribn. in Britt. & Brown, Illust. Fl. 3: 500./. 268a. June, 

 1898. "Dry soil, especially hillsides, New York and New Jersey to Missouri." This 

 was again published a as "n. sp." a few days later. "New England, southward to Vir- 

 ginia and westward to Texas." Both descriptions state that the sheaths are glabrous 

 or pilose, both illustrations indicate pilose sheaths. The type, in the National Her- 

 barium, is marked "P. linearifolium Scribn. Type." in Scribner's handwriting, and 

 is labeled "Washington, D. C, Vasey, 1882," but was probably collected in Maryland, 

 along the Potomac northwest of Washington, where this species is frequent in rocky 

 woods. The specimen is a tuft of culms 30 to 40 cm. high, with pilose sheaths, mature 

 primary panicles, and much reduced, nearly hidden secondary ones. The spikelets 

 are 2.2 to 2.4 mm. long. 



DESCRIPTION. 



Vernal form light green, in dense tufts, often surrounded by the withered, persistent, 

 more or less curled leaves of the previous year, the culms readily separating, 20 to 45 

 cm. high, very slender, erect, spreading or almost drooping at the summit, glabrous, 

 minutely puberulent or rarely pilose; sheaths usually equaling or exceeding the inter- 

 nodes, sparsely to densely papillose-pilose, the papillae often obscure; blades elongated 

 and erect, usually overtopping the panicles until maturity, 10 to 35 cm. long (the 

 lower shorter), 2 to 4 mm. wide, scabrous on both surfaces or often pubescent on the 

 lower, rarely on the upper surface, usually ciliate near the base with long hairs; pani- 

 cles finally long-exserted, 5 to 10 cm. long, half to two-thirda as wide, rather few- 

 flowered, the scabrous, flexuous branches re- 

 mote, ascending; spikelets 2.2 to 2.7 mm. long, 

 1.3 to 1.5 mm. wide, oblong-elliptic, obtuse, 

 sparsely pilose with weak, spreading hairs; first 

 glume one-fourth to one-third the length of the 

 spikelet, obtuse, or pointed by the inrolling 

 of the margins; second glume and sterile lem- 

 ma equal and equaling the fruit at maturity; 

 fruit 2 to 2.1 mm. long, 1.2 mm. wide, oval, 

 obscurely umbonate at the summit. 



Autumnal form similar, the reduced sec- 

 ondary panicles produced on short basal 

 branches mostly concealed in the tuft of basal leaves. 



While the typical form of this species is quite distinct from P. depauperatum, occa- 

 sional specimens, such as the following, seem to be intermediate between the two: 

 Burnham 24, Bush 1555, 4734; Hitchcock PL Kans. 880; Plank 40. In these the spike- 

 lets are about 3 mm. long and sometimes obscurely short-pointed. 



The following specimens have the sheaths glabrous or nearly so and approach the 

 closely allied P. werneri: Bissell 5541, Bush 4411A, Beam, Wells County, Indiana, in 

 1901, Hitchcock 598, Pollard, Washington, D. C, in 1897, Rose & Painter 8153. 



Fig. 140.— P. linearifolium. From 

 . type specimen. 



DISTRIBUTION. 



Dry woods, Maine to Kansas, south to Georgia and Texas. 

 Maine: Chesterville, Chase 3326; Fayette, Chase 3393; Canton, Parlin 1971. 

 Vermont: Barnet, Blanchard in 1888; Burlington, Hitchcock 598. 

 Massachusetts: Williamstown, Churchill in 1901. 



Connecticut: Southington, Andrews 49, Bissell 5541, 5542; Fairfield, Eames in 

 1895. 



" Scribn. U. S. Dept. Agr. Div. Agrost. Bull. 11 : 42. pi. 1. July 20, 1898. 



