HITCHCOCK AND CHASE NOKTH AMERICAN PANICUM. 



289 



174. Panicum leibergii (Vasey) Scribn. 



Panicum scoparium^ liebergii Vasey, U. S. Dept. Agr. Div. Bot. Bull. 8: 32. 1889. 

 "P. liebergii Scribn.)" is given as synonym, and "Plymouth County, Iowa (John 

 Lieberg) " [error for Leiberg] is cited. The type, consisting of two vernal culms, is in 

 Hitchcock's herbarium. The accompanying label reads: "Panicum Leibergii 

 Scribn. 1884. Plymouth Co., Iowa. 1878. Legit John Leiberg, " the specific 

 name, author, and date being in Scribner's writing. On the sheet is written in Vasey's 

 hand, "P. scoparium var. Leibergii V." 



Panicum scribnerianum leibergii Scribn. U. S. Dept. Agr. Div. Agrost. Bull. 6 : 

 32. 1897. No synonym is cited and "South Dakota: Brookings (Wilcox 16)" is the 

 only specimen mentioned. This name must however be considered a newcombina. 

 tion based on P. scoparium leibergii Vasey. The Wilcox specimen agrees with that 

 of Leiberg. 



Panicum liebergii Scribn. in Britt. & Brown, Illust. El. 3: 497. 1898. Based on 

 " Panicum scoparium Lam. var. Liebergii Vasey." This name was first mentioned 

 as a synonym under P. scoparium liebergii Vasey. a 



DESCRIPTION. 



Vernal form dull green, in clumps of few to several slender culms, 25 to 75 cm. 

 high, erect from a more or less geniculate base, pilose to merely scabrous; sheaths 

 shorter than the internodes, papillose-hispid with spreading hairs; ligules almost 

 obsolete; blades ascending or erect, rather thin, 6 to 15 cm. long, 7 to 15 mm. wide, 

 narrowed toward the rounded base, acuminate, papillose-hispid on both surfaces, 

 often sparsely so above, papillose-ciliate from one-third to half their length; 

 panicles finally long-exserted, 8 to 15 cm. long, less than half as wide, the flexuous 

 branches narrowly ascending or somewhat spreading at anthesis; spikelets 3.7 to 4 



Fig. 325.— P. leibergii. From type specimen. 



mm. long, 1.8 to 2 mm. wide,- oblong-obovate, turgid, strongly papillose-hispid with 

 spreading hairs; first glume more than half the length of the spikelet, pointed, second 

 glume and sterile lemma subequal, covering the fruit at maturity or the lemma slightly 

 exceeding it; fruit 3 mm. long, 1.7 to 1.8 mm. wide, obovate-oval. 



Autumnal form more or less leaning, sparingly branching from the middle and lower 

 nodes late in summer, the branches mostly simple, erect, the blades scarcely reduced, 

 usually exceeding the short-exserted panicles. 



41616 c 



«U. S. Dept. Agr. Div. Bot. Bull. 8: 32. 1889. 

 -vol 15—10 19 



