293 GRAMINE^. Aira. 



as the upper Horet. - Fl. Bor.-Am. ii. 243, t. 228; Torr. in Pacif. R. Eep. iv. 155. 

 Deschampsia elongata, Munro in Benth. PI. Hartweg. 342. 



San Francisco (Bolander, n. 1525, 6086) ; northward to Oregon Rail, Howell. Very variable 

 in heicrht ; sometimes purplish, but usually of a very bright but pale green. As noted by Torrey, 

 1. c, Hooker's otlierwise excellent figure lacks the conspicuous rudiment. 



4 A danthonioides, Trin. Culm slender, from a few inches to 2 feet high, 

 sometimes oeniculate and sparingly branched below : leaves very narrow, those of 

 the culm Tor 2 inches long, witli elongated ligules : panicle very loose and open, 

 about 1 the length of the culm, the lowermost rays in threes, the others m pairs or 

 solitary, distant, mostly spreading and few- (about 5-) flowered above the middle : 

 <dumes 3 lines long or more, linear-lanceolate, acuminate, 3-nerved, green and rough 

 on the keel : lower floret on a brief callus, the upper raised to the middle oi the 

 lower ; lower palet a little over a line long, the hairs at base J as long, shining below, 

 its truncate apex with 4 minutely ciliate teeth ; awn inserted just below the midd e, 

 about 3 times its length, light brown, twisted below and geniculate near the middle. 

 — Mem. Acad. St. Petersb. 1831, 57, and Icon. t. 255. Deschampsia cahjaua, 

 Presl Eel Hsonk. i. 251. B. danthonioides, Munro in Benth. PI. Hartweg. 342. 

 Trisetum glabrum, Buckl. in Proc. Acad. Philad. 1862, 100 ; Gray, in same, 337. 



Monte Diablo (Brewer, n. 1183) ; Oakland, etc. {Bolander, n. 6072) ; Sierra Nevada {Lemmon\; 

 northward to Oregon {NiMall, Hall) and eastward to Texas. Accorduig to Mr. Bolander it is 

 very abundant in some moist localities, forming the bulk ot the herbage. 



5 A latifolia, Hook. Culm from 1 to 2 feet high, its lower leaves 2 or 3 

 inches Ion" an. I about 3 lines wide, flat and smooth ; panicle at first included below, 

 with few slender rays which are densely flowered above ; spikelets very broad and 

 flattened • glumes about 3 lines long, ovate-lanceolate, acuminate, rough on the keel 

 above : lower palet about a line long, its silky hairs lialf as long or more, very broad, 

 irrecTularly 4-toothed and minutely pubescent above ; awn stout, attached just above 

 the^'middle, somewhat divergent, exceeding the palet but included by the glumes : 

 the second floret upon a very short joint which reaches only about one-fourth the 

 length of the lower floret; upper joint or rudiment very brief, but manifest. — 1^ 1. 

 Bor.-Am. ii. 243, t. 227. 



Orecron (Hall) ; Washington Territory {Cooper) ; Rocky Mountains This has not been detected 

 within the State, but is likely to occur in the northern portion. In his description Hooker gives 

 the awn as inserted below the midille, but figures it correctly. 



36. ARRHENATHERUM, Beauv. Oat-Grass. 



Panicle open. Spikelets subterete, 2flowered, with the rudiment of a third. 

 Lowest flower staminate, with a long bent awn below the middle of the back. Second 

 flower perfect, its lower palet bristle-pointed from near the tip. Otherwise as Avena. 



A genus of a single species, which is sometimes included in Avena, from which it is separated 

 by having its lowest flower staminate. 



1 A avenaceum, Beauv. Culm perennial, 2 to 4 feet high, with broad flat 

 soft' leaves ; panicle G to 8 inches long, narrow, spreading in flower : spikelets 4 or 5 

 lines long, pale and shining : lower glume about half as long as the upper, which 

 equals the florets : lower palet of staminate flower about 5-nerved, its awn twice its 

 length ; that of the upper floret 7-nerved, both hairy near the base. — Agrost. 5o, 

 t. \\, flg. 5 ; Reichenb. Icon. Fl. Germ. t. 104. 



A native of Euiope and naturalized as a weed ; occasionally sown as a meadow grass in the older 

 States. 



37. HOLCUS, binn. Velvet Grass. 



Spikelets crowded on the T)ranches of an open panicle and jointed upon their pedi- 

 cels, compressed, 2-flowered. Glumes boat-shaped, membrana(;eous, exceeding the 



