GRASS FA JULY 91 



Spikflpts not over 1 liiii' linij;. 



Shoatlis glabrous S. P. liitdln imeri. 



Sheaths pubescent. 



Plants velvety-pubescent 12. P. thermnle. 



Plants more or less pubescent but not velvety. 



Vernal blades glabrous above 10. P. oecidentalc. 



A'ernal blades pubescent above. 



Upper surface of blarles p'lo.se; HUliuunal fiirni deeumbeut-spreacling 



11. P. pacifi'Cum. 

 Upper surface of blades appressed-pubescent ; autumnal form erect or ascend- 

 ing 9. P. huachucae. 



A. True Panicum. Annuals or perennials of various habit, but not forming 

 winter rosettes of leaves different in appearance from the culm leaves. 

 nor presenting: a distinct vernal and autumnal aspect. 



1. P. arizonicum Scribn. & Merr. Annual; culms usually branching from 

 the base, glabrous except below the panicle, 8 inches to 2 feet high ; nodes 

 sometimes slightly puliescent : sheaths glabrous to strongly papillose-pubescent; 

 blades 2 to 6 inches long, 3 to 6 lines wide, glabrous or papillose-hispid beneath ; 

 panicles long-exserted, finely piibescent and copiously papillose-hirsute, 3 to 9 

 inches long, the branches solitary, asi-ending, few-flowered; spikelets nearly 2 

 lines long, obovate-elliptical, abrujitly pointed, densely hirsute to glabrous, 

 borne on very short appressed branchlets. 



Open ground; Jamaeha, San Diego Co., Catihij (the only California specimen 

 seen) to western Texas and south into southern Mexico. 



Ref.— P.V-Nicu.M .ARIZONICUM Scribn. & Merr. U. S. Dept. Agr. Div. Agrost. Circ. 32: 2. 1901. 



2. P. dichotomiflorum Michx. Annual, usually much-branched from a ge- 

 niculate base, smooth throughout ; culms rather succulent, 2 to 3 feet high ; 

 blades 4 to 20 inches long, about 14 inch wide; panicles 4 to 12 inches long, 

 finally spreading: spikelets li/4 lines long, narrowly oblong-ovate, acute, 

 faintly 7-nerved, the first glume short, truncate, about i/t the length of the 

 spikelet. 



Low ground and cultivated soil; Fresno, Bioletti 140, the only California 

 specimen seen. Common in Eastern U. S. 



Refs. — Panicum dichotomiflorum Michx. Fl. Bor. Am. 1: 48. 1803. This species has 

 been incorrectly referred by American botanists to P. proliferum Lam. of the Old World. 



3. P. capillare L. Old-witch Grass. Annual, erect, 1 to 2 feet high ; foli- 

 age pMpil]os(>-hispid ; blades 4 to 10 inches long, I/4 to V2 inch wide; panicle 

 large and diffuse, often % the length of the entire plant, included at the base 

 until maturity, the whole panicle finally breaking away and rolling before the 

 wind ; spikelets about 1 line long, elliptic ; first glume acute, 1/. as long as 

 spikelet, 5 to 7-nerved. 



Open ground, cultivated soil, and river banks, a common weed in Eastern 

 n. S. Pinegrove, Amador Co., TJansen 599, the only specimen seen from Cali- 

 fornia. 



Refs. — Panicum capillare L. Sp. PI. .'SS. 1753. The species described under this name 

 in western floras is usually P. barbipulvinatuin. 



4. P. barblpulvinatum Nash. Closely resembling P. capillare of which it is 

 the western ri'iircseiitative, but differing in its stouter habit, shorter, less 

 pubescent blades crowded toward the base of the plant, and especially in the 

 larger spikelets, about W^ lines long. 



Open ground and cultivated soil at moderate altitudes throughout the state 

 and extending from Rritish Columbia to Texas. 



