50 Bulletin VII. 1. 



spikelets rather smaller and less distinctly racemose than in P. 

 Walteri, which resembles P.conunutatuvi in general habit of growth. 



22. Panicum sphserocarpon Ell. . 



Plate XIII. Figures 51, 52. 



A tufted, erect or ascending perennial, ten to twenty-four inches 

 high, with rather broad, firm and nearly erect leaves, and diffuse 

 many-flowered panicles, usually about three inches long. Culms 

 simple or finally much branched near the base, smooth or usually 

 pubescent with erect hairs at the nodes. Sheaths longer, or more 

 often shorter than the internodes, ciliate along the overlapping or 

 outer margin, otherwise smooth; ligule none; lowermost leaves 

 broadly ovate, many-nerved, minutely roughened along the strongly 

 cartilaginous margins; the leaves of the culm two to four inches long, 

 one-fourth to three-fourths of an inch wide, cordate-clasping at the 

 base, very acute, many-nerved, lower surface smooth, the upper 

 scabrous, margins cartilaginous and minutely serrulate, with a 

 few long hairs near the base; uppermost leaf two to three inches 

 long. Panicle ovate-pyramidal, two to three, rarely four inches 

 long, branches very slender, divided to the base, pedicels usually 

 much longer than the spikelets. Spikelets nearly spherical, less 

 than a line long; first glume minute, the second and third glumes 

 nearly equal, seven- to nine-nerved, minutely pubescent; the third 

 with a small, hyaline palea; fourth glume smooth and shining, 

 very obtuse. Dry open woods and fields. May — June. 



This differs from P. 77iicrocarpon in its shorter, narrower, and 

 more erect leaves, bearded nodes, shorter leaf-sheaths and smaller 

 panicle. It also blooms in advance of P. 7?iicroca7'pon and the culms 

 are more often branched. In the open the culms are often nearly 

 prostrate. 



23. Panicum microcarpon Muhl. 



Plate XIV. Figures 53, 54. 



An erect or ascending perennial one to three, usually about two 

 feet high, with smooth, broad, spreading leaves and diffuse, many- 

 and very small-flowered panicles, usually four to five inches long. 

 Culms smooth, usually simple or finally sparingly branched. 

 Sheaths smooth, exceeding the internodes, ligule none; basal leaves 

 crowded, ovate, one to two inches long, one-half to three-fourths of 

 an inch wide, many-nerved, with strong cartilaginous and scabrous 

 margins, those above five to ten inches long, lanceolate from a 

 cordate clasping base, very acute, nerves prominent, ciliate on the 

 minutely scabrous margins near the base; the uppermost leaf three 

 to eight, usually five to six inches long and often an inch wide. 

 Panicle three to eight inches long, ovate-elliptical, the very slen- 

 der branches compound to the base; the capillary pedicels usually 

 longer than the numerous spikelets. Spikelets broadly obovate or 

 nearly spherical, three-fourths of a line long; first glume minute, the 

 second and third nearly equal, seven-nerved, minutely pubescent; 

 the third with a small hyaline palea; the fourth glume white, 

 shining, obtuse. 



