396 



ORDER 155. GRAMINE^E. 



1 A. atropurpiirea Wahl. In tufts, If, very slender; Ivs. flat; pan. thin; awt 



stout, twice as long as the pale. 11 High Mts., N. Eng. and N. Y. August. 



2 A. flexuosa. L. (f) In large tufts, smooth, 1 2f; Ivs. setaceous, mostly radical; 



pan. loose, with long flexuous spreading branches; awn geniculate, twice longei 

 tlian the pale (m). 2f Dry hills : common. June. 



3 A. crespltosa L. (n) Tufted, glabrous, 18 30'; Ivs. narrow-linear, flat ; pan. ob- 



long, finally diffuse; awn straight, as long as the pale, which is longer than the blu 

 is<h glumes, (o, spikelet, p, fl.) n Swamps, northward. May. 



30. DANTHONIA, DC. Spkl. 2-7-flwd. Gl. 2, subequal, 

 cuspidate, longer than the whole spikelet of fls. Pales hairy at 

 \ ase, lower one bidentate and awned at apex, upper obtuse, en- 

 lire. Awn flattened and twisted at base, y Fls. racemous. 



I D. spioata. R. & S. (a) Lvs. narrowly-linear, shorter than the 

 nodes; culm 1 2f, slender; spkl. few (about 6), in a subsimplc r;i 

 gl. 4 5" ; fls. (b) about 7, pubescent. Lvs. mostly radi- 

 cal, in little tufts. Dry hills : com. June Aug. 



fl. roniprtxsa. Lvg. longer than the internodes ; spkl. 

 about 4 in the simple raceme; gl. twice longer than the 

 spikelet. Onondaga Co.. N. Y. (S. A*. Cowles). (D. com- 

 pressa, Austin ?) These characters are not constant. 



< D. sericea Nutt. Taller (2 2Jf); Ivs. and sheaths 

 silky-hirsute; spkl. 917, evidently paniculate; gl. 89"; 

 fls. about 7, densely clothed with silvery-silky hairs ; awns brown at base 

 No. 1), very long. Rare N., common S. June. 



31. AVENA, L. OAT. OAT G. Spkl. 2-5-flwd. 

 Gl. 2, loose, thin, awnless, large. Pales 2, becom- 

 ing coriaceous, the lower bifid, bearing (mostly) a 

 bent or twisted awn on the back ; upper pale coat- 

 ing the oblong grain. Fls. paniculate. 



ABRHENATHEIUJM. Glumes unequal, 2-flowered, 



with a rudiment of a third; lower flower 



staminate and awned. Tall No. 1 



Ara6psis. Gl. subequal, 2-flwd., both flowers S , 



no rudiment. Dwarf Nos. 2, 



AVENA. Gl. equal, longer than the 2 perfect 



flowers, strongly striate Nos. 4, 5 



1 A. eliitior L. (a./) Culm erect, 2 4f; Ivs. lance-linear; pan. narrow, 710'. nod- 



ding ; upper gl. (y) and pales 4", lower gl. 2" ; awn bent, twice longer than the i ale. 

 U A tall handsome grass. Eur. (Arrhenatherum avenaceum Br.) May July. 



2 A. prajcox Beauv. (d) Culms tufted, erect, 25' ; Ivs. setaceous ; pan. dense, ob- 



tony, i 1' ; }il- ('') equaling the fls. (c) ; awns bent, twice longer, n N. Y. to Va. Jn. 



3 A. caryopliylla L. Culms 5 10'; Ivs. very narrow; pan. loose, open; glumes 



silvery-purple, scarce 1", pales shorter, awns exserted. Dry fields. M. Eur. 



4 A. SATIVA. Common Oat. Culm terete, erect, 2 4f: Ivs. lance-linear; pan. loo:>e, 



pyramidal; spkl. large, pendulous; both fls. 9, 7", the lower mostly awned ; lx>th 

 pales coating the nutritious grain. Cultivated, common. June. 



/3. nig-ra. Black Oats. Pales dark brown, almost black, without awns. 



y. Hrcuiulii. Horse-mane Oat. Panicle one-sided, nodding; awns short. 



5 A. STKRILIS. Animated 0. Spkl. 5-flwd., 2 lower fls. each with hairy pales and a 



long bent awn which is so sensitive to moisture as to be kept in motion by the ordi- 

 nary changes in the air. From Europe. Cult, as a curiosity. (T) 4f. July. August. 



