HITCHCOCK AND CHASE—NORTH AMERICAN PANICUM. 279 
Spikelets 3.2 to 3.3 mm. long; blades firm, 
sheaths or some of them more or less 
hispid .....--.--------------eee eee 171. P. seribnerianum. 
Spikelets not over 3 mm. long; blades rather 
thin; sheaths or some of them glabrous 
or sparsely hispid...........-.------- 170. P. helleri. 
168. Panicum wilcoxianum Vasey. 
Panicum wilcorianum Vasey, U.S. Dept. Agr. Div. Bot. Bull. 8: 32. 1889. “‘Ne- 
braska (Dr. T. E. Wilcox).’’ The type, in the National Herbarium, consists of several 
vernal culms beginning to branch, 13 to 17 cm. high, with scarcely mature primary 
panicles. On the sheet is written in Vasey’s hand, “ Panicum Wilcoxianum, Vasey 
n. sp., Niobrara Ft., Nebraska. Dr. T. FE. Wilcox, 1888.” 
DESCRIPTION. 
Vernal form dull green; culms usuallyin dense tufts, erect, 10 to 25 em. high, copi- 
ously papillose-hirsute, as are the rather loose, usually overlapping sheaths; ligules 
about 1 mm. long; blades firm, erect or ascending, 5 to 8 cm. long, 3 to 6 mm. wide, 
broadest toward the base (this scarcely 
wider than the wide sheath), commonly 
involute-acuminate, long-hirsute on both 
surfaces; panicles finally exserted, often 
equaled or excceded by the upper blades, 
2 to 5 cm. long, about half as wide, or some- 
times more expanded at anthesis, rather 
densely flowered; spikelets 2.7 to 3 mm. 
long, 1.5 mm. wide, obovate-elliptic, papil- 
lose-pubescent; first glume about one-third 
as long as the spikelet, pointed or obtuse; 
second glume slightly shorter than the fruit 
and sterile lemma; fruit 2.4 to 2.5 mm. long, 1.3 to 1.4 mm, wide, elliptic. 
Autumnal form branching from all the nodes, forming bushy tufts with rigid, erect 
blades much overtopping the reduced panicles; branches appearing early, usually 
before the maturity of the primary 
panicles; secondary spikelets usually 
more turgid than those of the primary 
panicles. 
Fia. 313.—P. wilcozianum. From type specimen. 
DISTRIBUTION. 
Prairies, Manitoba to North Dakota 
and south to Jowa and Kansas. 
Minnesota: Winona, Holzinger 28 
in part (Biltmore Herb.). 
Manitrosa: Sewell, Macoun 13227. 
Nortnu Daxora: Towner, Lunell 
in 1908. 
Soutrn Daxora: Brookings, Williams in 1891, E. N. Wilcox 14; Roberts County, 
S. D. Agr. Col. & Exp. Sta. 4167; Rosebud, Wallace in 1896; Jamesville, 
Bruce 80. 
Iowa: Missouri Valley, Pammel 3198; Gilbert Station, Carver in 1894. 
Fic. 314.—Distribution of P. wilcorianum. 
