142 CONTRIBUTIONS FROM THE NATIONAL BEBBABIUM. 



DESCRIPTION . 



Plants annual; culms erect or sometimes decumbenl at base, as much as 1 meter or 

 even 1.5 meters tall, glabrous; sheaths glabrous; ligule wanting, theligular area some- 

 times slightly pubescent; blades 5 to 15 mm. wide, scabrous on the margins, some- 

 times on the upper surface; panicles erect (or nodding), 10 to 20 cm. long, the axis 

 scabrous; racemes spreading, ascending, or appressod, the lower somewhat distant, as 

 much as 10 cm. long, sometimes branched, the upper approximate, shorter, the rachis 

 scabrous, hispid, especially at the base; spikelets crowded, about '■'< mm. Long, exclud- 

 ing the awns, strongly hispid or papillose-hispid on the nerves, hispiduloua on the 

 internerves; sterile lemma with a well-developed palea, neuter, the awn variable in 

 length, mostly 5 to 10 mm. long on at least a part of the spikelets, sometime- as much 

 as 3 cm. long; fruit elliptic, turgid, narrowed into a cusp or point, 2.5 to 3 mm. long, 

 whitish or brownish. 



In America the species may be divided into three geographical races. Those are 

 fairly distinct over a certain range, but overlap and intergrade to such an extent that 

 they can not be recognized as distinct species. The three races were originally 

 described as Panicum crusgalli L., Oplismenus crus-pavonis H. B. K., and 0. zelay- 

 ensis H. B. K., respectively. The first is a native of the Old World and also of the 

 eastern United States. The second is found in Brazil and extends north into Mexico 

 and the West Indies. The third has its center of distribution on the Mexican plateau 

 and extends into the southwestern United States. However, there are many speci- 

 mens in our herbaria that can not be definitely assigned to any one of these forms. 

 Hence in the distribution given under each race the placing of some of the speci- 

 mens under a given subspecies is arbitrary. 



European botanists generally distinguish two forms of the first race, Panicum 

 crusgalli, a long-awned and a short-awned, and recent works generally apply the 

 varietal names, longianstata to the first, and breviaristata to the second. Ascheraon 

 and Graebner, ' whose recent work is representative for Europe, include the two 

 forms under Panicum as P. crusgalli longiaristatum Doell 2 and P. crusgalli breviaru- 

 tatum Doell. 2 



Pursh 3 first distinguished the forms in America as Panicum crusgalli var. aristatum 

 and P. crusgalli var. mite. 



The robust form with large compound panicle of short-awned or merely pointed 

 spikelets may look very distinct, but the intergrades are so numerous that it can 

 scarcely receive recognition as a variety. For the sake of convenience it is here 

 segregated as a variety and the specimens of Echinochloa crusgalli are more or less 

 arbitrarily assigned to the two forms, the awned under Echinochloa crusgalli, the nearly 

 awnless under E. crusgalli mitis. 



A third form of the first race, originally described as Panicum frumentaceum Roxb., 

 is rather more distinct because, being cultivated, the slight differences are per- 

 petuated. 



DISTRIBUTION. 



Moist open ground, ditches, cultivated fields, and waste places. New Brunswick to 

 Washington, south to Florida and California: warmer parts of the Eastern Hemisphere. 

 The following specimens are referred to the typical or awned form; some of them, 

 however, approach variety mitis, but at least a part of the spikelets have awns as 

 much as 3 mm. long. Commonly known as barnyard <;rass. 

 New Brunswick: Shediac Cape, Hubba rd 755. 763. 

 Quebec: Oka, Victorin 3022. 

 Ontario: Amherstburgh, Macoun 26319. Kingston, Fowler in L897 and 1905. Gait, 



Herriot in 1908. Larma r Dodge 129. 

 Manitoba: Branchon, Macoun 13226. 



1 Syn. Mitteleur. Fl. 2: 69. 1898. 3 Fl. Amer. Sept. 66. 1814. 



2 Fl. Bad. 1:232. 1857. 



