LXXXIX. GRAMItfE^. 521 



Britain, having been formerly found in Scotland, and moire recently in 

 the moors round Oakmere in Cheshire, and a variety, Hookeri, Syme, 

 about Lough Neagh, in, Ireland. Fl. summer. 



[4. C. strigosa, Hartm. (fig. 1192). An Arctic and subarctic species, 

 has very recently been discovered in Caithness ; it most closely re* 

 seiubles 0. itricta, but has larger spikelets and more acuminate glumes. J 



XVIL AIRA. AIRA. 



Very near Avena in all essential characters, but the spikelets are 

 mucji smaller, usually with two flowers, only or rarely a single one, the 

 flowering glumes thinner and more scarious, not projecting beyond the 

 outer glumes, and the hair-like awn on their back much shorter than 

 in Avena. 



The species are few, chiefly European and north Asiatic, a very few 

 extending into North America, or reappearing in the southern hemi- 

 sphere. 



Panicle very loose, with capillary, spreading branches. 



Stems 2 to 4 feet high. Leaves in large tufts, flat and rough. 



Awns shorter than the glumes 1. A. ccespitosa. 



Stems 1 to 1$ feet. Leaves rolled in on the edges. ~Awns pro- 

 jecting from the outer glumes 2. A. flexuosa. 



Stems 4 to 6 inches. Leaves fine and Short. Awns shortly 



protruding 6. A. caryophyllea. 



Panicle dense and narrow. Stems 3 to 6 inches. 



Spikelets about 2 lines long. Awns thickened at the top, 



shorter than outer glumes 3. A. eanescens. 



Spikelets rather more than 1 line. Awn hair-like, shortly 



protruding ... 4. A. prcecox. 



1. A. caespitosa, Linn. (fig. 1193). Tufted A. A. tall perennial, 

 forming large, dense tufts, with rather stiff, flat leaves, very rough 

 on the upper surface. Stems 2 to 4 feet, bearing an elegant panicle 6 

 inches to near a foot long, with spreading, slender, almost capillary 

 branches. Spikelets silvery-grey or purplish, about 1^ lines long. 

 Outer glumes rather unequal, lanceolate and pointed. ^Flowering 

 glumes scarcely projecting from the outer ones, minutely toothed or 

 jagged at the top, with a fine, hair-like awn inserted near their base, 

 and not so long as the glume itself. Deschampsia ccespitosa, Beauv. 



In moist, shady places, throughout Europe, from the Mediterranean 

 to the Arctic regions, and the temperate and mountain regions of the 

 northern and southern hemispheres. Abundant in Britain. FL summer. 

 A. alpina, Linn., is a variety which in its least altered form only differs 

 in its lower stature, with shorter leaves, with the glumes more or less 

 enlarged, the awn adhering to it so much the higher as the glume is 

 more altered. The whole panicle is usually viviparous, all the glumes 

 being elongated, foliaceous, without awns, and containing very imper- 

 fect flowers or none. It frequents considerable elevations, or high 

 latitudes, and is common in the higher mountains of Scotland. 



2. A. flexuosa, Linn. (fig. 1194). Wavy A. A much smaller and 

 more slender plant than the ordinary form of A. ccespitosa, from 1 to'l 

 feet high, with very narrow leaves rolled inwards on the edges, and 

 almost subulate. Panicle spreading, but not above 2 or 3 inches long ; 



