AVENA. 



GRAMINEiE. 



453 



Perennial. Culm 2-3 feet high, slender, erect. Leaves flat, 2-3 inches long : ligule oblong. 

 Panicle oblong, yellowish green. Spikelets ovate, much compressed, mostly 2-flowered, with 

 an abortive rudiment. Glumes nearly equal, shorter than the flowers, acuminate or mucro- 

 nate, rough on the keel. Upper perfect flower on a hairy pedicel. Lower palea lanceolate, 

 acuminate, bicuspidate : awn slender, inserted below the tip, twisted : upper palea shorter, 

 lacerate at the tip. 



Wet meadows : rare. Fl. June. This grass does not accord in all respects with the cha- 

 racters of Avena, but it rather belongs to that genus than to Trisetum or Aira. 



2. Avena striata, Michx. Purple Wild-oat. 



Panicle nearly simple, loose, few-flowered ; spikelets 3 - 5-flowered, somewhat terete, the 

 flowers bearded at the base ; lower palea with a slender nearly straight awn below the tip. — 

 Mich. fl. 1. p. 73 ; Beck, hot. p. 403 ; Kunth, enum. 1. p. 303; Hook. fl. Bor.-Am. 2, 

 p. 244, not of Lam. Trisetum purpurascens, Torr. fl. 1. p. 127. 



Perennial. Culm 2-3 feet high, erect, simple, smooth. Leaves 3 - 4 inches long, and 

 about 2 lines wide, smooth ; the sheaths close, conspicuously striate : ligule short. Panicle 

 3-6 inches long, consisting of few nearly simple branches, each bearing 1-3 spikelets. 

 Flowers rather remote, each with a tuft of short hairs at the base. Glumes unequal, of a 

 reddish purple color, acute ; the lower one indistinctly 3-nerved ; upper 5-nerved. Lower 

 palea strongly 7-nerved, attenuated and 2-cleft at the summit ; the awn bent obliquely : upper 

 palea lanceolate, much shorter than the lower, entire, ciliate on the margin, 

 f Banks of rivers, and moist woods : northern and western counties. Fl. July. 



30. ARRHENATHERUM. Beauv. Agrost. p. 55 ; Kunth, enum. 1. p. 307. oat-grass. 



[From the Greek, arrhen, male, and ather, an awn ; the staminate flower being awned.] 



Spikelets 2-flowered : lower flower staminate ; the lower palea with a twisted awn below the 

 middle. Upper flower perfect ; the lower palea with a short straight bristle below the tip. 

 — Panicle loose. 



1. Arrhenatherum avenaceum, Beauv. Grass of the Andes. Oat-grass. 



Beauv. Agrost. p. 55. t. 11. /. 5; Torr. fl. 1. p. 130; Kunth, enum. ]. p. 307. A. 

 Kentuckense, Torr. 1. c. Avena elatior, Linn.; Muhl. gram. p. 185; Bigel. fl. Bost. p. 

 33 ; Beck, hot. p. 403 ; Darlingt. fl. Cest. p. 66. 



Perennial. Rhizoma creeping. Culms 2-3 feet high. Leaves roughish on the margin ; 

 sheaths smooth : ligule short. Panicle oblong, at first somewhat contracted, finally spreading ; 

 the branches in threes or semiverticillate. Spikelets brownish. Glumes unequal ; the lower 

 one shorter than the flowers. Awn of the staminate flower much contorted. Lower palea 

 of the perfect flower sometimes awnless : upper palea with an awnlike rudiment or continua- 

 tion of the rachilla at its base. 



