396 



ORDER 155. GRAMINE^. 



1 A. atropurpurea Wahl. In tufts, If, very slender; Ivs. flat; pan. thin; awi. 



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



2 A. flexuosa L. (0 In large tufts, smooth, 1 2f; Ivs. setaceous, mostly radical; 



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

 than the pale (m). li Dry hills : common. June. 



3 A. crespitosa L. (n) Tufted, glabrous, 1830'; Ivs. narrow-linear, flat; pan. ob- 



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

 ieh glumes, (o, spikelet, p, fl.) u Swamps, northward. May. ' 



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

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

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

 tire. Awn flattened and twisted at base, if Fls. racemous. 



1 D. Kpic-uta. R. & S. (a) Lvs. narrowly-linear, shorter than the inter- 



ncdcs; culm 1 2f, slender; spkl. few (about 6), in a subsimple raceme; 

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

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



ft. comprinsa. L\s. longer than the internode- ; spkl. 

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

 spikdet. Onondaga Co.. N. Y. (S. N. Cowlts). (D. con> 

 pressa, Austin?) These characters are not constant. 



2 D. sericea Nutt. Taller (2 2|f); Ivs. and sheaths 



?ilky-himite; epkl. 917, evidently paniculate; gl. P l j"; 



fl*. about 7, densely clothed with silvery-silky hairs ; awns brown at base (is in 



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. 



ARRHENATHERCM. Glumes unequal, 2-flowered, 

 with a rudiment of a third ; lower flower 



staminate and awned. Tall No. 1 



AIROPSIS. Gl. subequal. 2-flwd., both flowers ? , 



no rudiment. Dwarf Nos. 2, 3 



AVENA. Gl. equal, longer than the 2 perfect 



flowers, strongly striate Nos. 4. 5 



1 A. cljitior L. (fl, /) Culm erect, 2 4f; Ivs. lance-linear; pan. narrow, 7 10', nod- 



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

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



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



to'iyi \ 1' ; Rl- W equaling the fls. (c) ; awns bent, twice longer, if 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. loose, 



pyramidal ; spkl. large, pendulous ; both fls. , 7", the lower mostly awned ; both 

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



|8. nlg-ra. Black Oats. Pales dark brown, almost black, without awns. 



y. secunda. Horse-mane Oat. Panicle one-sided, nodding; awns bhort. 



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. 4f. July. August. 



