154 



CONTRIBUTIONS FKOM THE NATIONAL HERBARIUM. 



in Nash's herbarium, consists of five clumps of several culms each, 7 to 40 cm. high, 

 with mature primary and immature secondary panicles, and spikelets 3 to 3.2 mm. long. 

 Panicum pammeli Ashe, N. C. Agr. Exp. Sta. Bull. 175: 116. 1900. "Prairies of 

 Iowa, June." The type, in Ashe's herbarium, collected by R. I. Cratty, June 12, 

 1881, has spikelets 3.1 to 3.2 mm. long. 



DESCRIPTION. 



Vernal form similar to that of P. depauperatum, more strict in habit, and in smaller 

 tufts, more constantly pilose and usually papillose, the blades on the average longer 



and narrower, sometimes 25 cm. long, 

 pubescent on the lower surface ; panicles 

 smaller and narrower, the branches erect, 

 hence appearing more densely flowered; 

 spikelets 2.7 to 3.2 mm. long, 1.6 to 1.7 

 mm. wide, oval, blunt, sparingly pilose; 

 first glume one-fourth to one-third the 

 length of the spikelet, acute or obtuse; 

 second glume and sterile lemma equal, 

 obtuse, not extended beyond the fruit, 

 strongly 7 to 9-nerved; fruit 2.4 mm. 

 long, 1.5 to 1.6 mm. wide, obovate- 

 oval, rounded and minutely umbonate at the summit. 



Autumnal form with secondary panicles usually more numerous than in P. depau- 

 peratum and sometimes produced from the second node. 



Fig. 138. — P. perlongum. From type specimen. 



DISTRIBUTION. 



Prairies and dry soil, Michigan and Manitoba fo Texas. 

 Indiana: Elkhart County, Deam 6753. a 



Illinois: Hanover, Gleason & Gates 2530; Naperville, Umbach 1670; Wady Petra, 

 V. H. Chase 460, 1158, 1731, in Kneucker Gram. Exs. 547; Peoria, Brendel, 

 McDonald 18. 

 Michigan: Keweenaw County, 



Farwell 755. 

 Wisconsin: Racine, Wadmond in 



1901. 

 Minnesota: Lake City, Manning 



in 1883 (Gray Herb.). 

 Manito ba : Lake Winnipeg Valley, 



Bourgeau in 1837 (Gray Herb.). 

 South Dakota: Custer, Rydberg 



1100; Clark, Griffiths 863. 

 Iowa: Ames, Ball SO, 145; Clinton, 



Vasey; Iowa City, Somes 245. 

 Nebraska: Ewing, Bates 1120. 

 Missouri: Lees Summit, Bu^h 3089. 

 KANSAa; Manhattan, Hitchcock 2501, 2509. 

 Texas: Llano County, Nealley 79; Wallisville, Wallis 38. 

 Oklahoma: Creek Nation, Carleton 98. 



oThis specimen and those of P. xalapense, P. ashei, and P. commutatumhovo. Indiana 

 were received too late for representation in the maps. 



Fig. 139.— Distribution of P. perlongum. 



