396 



ORDER 155. GRAMINE^E. 



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



stout, twice as long.as the pale, u 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 longei 

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



3 A. cwspltosa 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 bin 

 ish glumee. (0, spikelet, p, fl.) y. Swamps, northward. May. 



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

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

 be.se, lower one bidentate and awned at apex, upper obtuse, en- 

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



1 I>. spicata R. & S. (a) Lvs. narrowly-linear, shorter than the inter- 



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

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

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



ft. compr^sna. Lvs. longer than the internode* ; spkl. 

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

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

 pressa, Austin ?) These characters are not constant. 



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



silky-hirsute ; gpkl. 9 17, evidently paniculate : gl. 8 9"; 



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



ARRHENATHERUM. 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 9 , 



no rudiment. Dwarf Nos. 2, 3 



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, 7 10', nod- 



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

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



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



lorif/, i 1' ; gl. (d) equaling the fls. (c) ; awns bent, twice longer, n N. Y. to Va. Jn. 



3 A. earyopliylla L. Culms 510' ; 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. 55 , 7", the lower mostly awned ; both 

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



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



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



5 A. STERILIS. 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. 



