MANUAL OF THE GRASSES OF THE UNITED STATES 363 



slender straight awn shorter than the awns of the glumes. Usually decumbent 

 annuals or perennials with flat scabrous blades and dense, bristly, spikelike 

 panicles. Type species, Polypogon monspeliensis. Name from Greek polus, 

 much, and pogon, beard, alluding to the bristly inflorescence. 



One species, P. monspeliensis, is palatable to stock and is sometimes suffi- 

 ciently abundant on low meadows to be of importance in the West. 



Plants annual. 



Glumes slightly lobed, the lobes not ciliate 1. P. monspeliensis. 



Glumes prominently lobed, the lobes ciliate-fringed _ 2. P. maritimus. 



Plants perennial. 



Glumes gradually narrowed into the awn ..... 5. P. elongatus. 



Glumes abruptly rounded at summit. 



Awns rather stiff and straight; glumes 2.5 to 3 mm. long 3. P. interruptus. 



Awns delicate, flexuous; glumes 1.5 to 2 mm. long 4. P. australis. 



1. Polypogon monspeliensis (L.) long or the uppermost longer; blades 

 Desf. Rabbitfoot grass. (Fig. 510.) commonly 4 to 6 mm. wide; panicle 

 Annual; culms erect or decumbent at oblong, 5 to 15 cm. long, more or less 

 base, 15 to 50 cm. tall (sometimes de- interrupted or lobed; glumes equal, 

 pauperate or as much as 1 m. tall); 2.5 to 3 mm. long, scabrous, the awns 

 ligule 5 to 6 mm. long; blades in aver- 3 to 5 mm. long; lemma smooth and 

 age plants 4 to 6 mm. wide; panicle shining, 1 mm. long, minutely toothed 

 dense, spikelike, 2 to 15 cm. long, 1 to at the truncate apex, the awn exceed- 

 2 cm. wide, tawny yellow when ma- ing the glumes. % (P. lutosus of 

 ture; glumes hispidulous, about 2 mm. Manual, ed. 1, a doubtful species of 

 long, the awns 6 to 8 mm. long, rarely Europe.) — Ditches and wet places at 

 longer; lemma smooth and shining, low altitudes, British Columbia to 

 about half as long as the glumes, the California, east to Louisiana; Ne- 

 delicate awn slightly exceeding them, braska; Oklahoma; south to Argen- 

 © — Ballast and waste places, New tina. 



Brunswick to Georgia, Oklahoma, 4. Polypogon australis Brongn. 

 and Texas, west to Alaska and Cali- (Fig. 513.) Perennial; culms as much 

 fornia, infrequent in the East, mostly as 1 m. tall; ligule 2 to 3 mm. long, 

 confined to the coastal States, a com- fragile; blades commonly 5 to 7 mm. 

 mon weed in the Western States; at wide; panicle soft, lobed or inter- 

 low altitudes, south to Argentina; in- rupted, mostly 8 to 15 cm. long, the 

 troduced from Europe. numerous awns purplish; glumes 1.5 



2. Polypogon maritimus Willd. to 2 mm. long, hispidulous, the awn 

 (Fig. 511.) Annual; culms 20 to 30 flexuous, delicate, 4 to 6 mm. long; 

 cm. tall, upright or spreading; ligule lemma about two-thirds as long as 

 as much as 6 mm. long; blades usu- the glumes, the awn about 3 mm. 

 ally less than 5 cm. long, 2 to 4 mm. long. % (P. crinitus Trim, not 

 wide; panicle mostly smaller and less Nutt.) — Introduced at Bingen, 

 dense than in P. monspeliensis; Wash.; Chile and Argentina, 

 glumes about 2.5 mm. long, hispid- 5. Polypogon elongatus H. B. K. 

 ulous below, the deep lobes ciliate- (Fig. 514.) Perennial; culms rather 

 fringed, the awns 7 to 10 mm. long; coarse, as much as 1 m. tall, erect or 

 lemma awnless. O — Introduced, decumbent at base ; sheaths glabrous ; 

 Georgia (Tybee Island) ; Nebraska, ligule prominent, as much as 8 mm. 

 California (Napa and New York long, lacerate, decurrent; blades 10 to 

 Falls, Amador County) ; Mediterra- 20 cm. long, 6 to 8 mm. or as much 

 nean region. as 10 mm. wide, very scabrous; pan- 



3. Polypogon interruptus H. B. K. icle erect or nodding, loose, inter- 

 Ditch polypogon. (Fig. 512.) Peren- rupted, 15 to 30 cm. long, the branches 

 nial; culms tufted, geniculate at base, clustered, densely flowered to the 

 30 to 80 cm. tall; ligule 2 to 5 mm. base; glumes about 3 mm. long, 



