TRIANDRIA— DIGYNIA. Aira. 103 



furrowed and roughish above ; their margins involute by drying j 

 radical ones copious. Sheaths smooth. Stipula oblong, acute, 

 often cloven. Panicle large, spreading horizontally, with innu- 

 merable capillary, elastic, angular, wavy, rough branches. Fl. 

 solitary, very small, purplish, shining, erect. Cal. pale and mem- 

 branous at the edges ; purple at the back, with a rough keel. 

 One floret sessile ; the other on a short hairy stalk, whichis more 

 or less extended upwards, above the floret ; both beset with hairs 

 at the base, which are about half as long as the keeled, very ab- 

 rupt, notched valves of the corolla. Awn bent, springing from near 

 the base of the outer valve of each floret, and seldom rising above 

 it. Anth. purple, short and thick, concealing the still shorter 

 styles and stigmas. This and the next approach Arunclo in habit, 

 and even in the essential character of the hairs surrounding each 

 floret. But in Arundo those hairs are always more copious, and 

 as long as the glumes. All the following species moreover have 

 a tuft of hair at the base of each floret, but in general so minute, 

 that it could by no means authorize their union with Arundo. 

 They rather agree with Avena in this character, the nature of 

 their awns, and structure of their glumes. 



4. A. alpina. Smooth Alpine Hair-grass. 



Panicle rather close and upright. Florets the length of the 

 calyx, acute ; one of them on a smooth stalk. Awn short, 

 from near the top of the outer valve. Leaves involute- 

 awl-shaped, with smooth sheaths. 



A. alpina. Linn. Sp. PL 96. Fl. Suec. ed. 2. 25. Willd. v. 1 . 379. 



Wahlenb. Lapp. 3i. t.3. Hook. Scot. 29. 

 A. laevigata. Engl. Bot. v. 30. t. 2102. Comp. 14. 



On the highland mountains, in many places, as well as on the sea 

 shore of Scotland. 



On the lofty mountains of Clova, Angusshire, and by the sea side 

 near Dundee. Mr. G. Don. Ben Lomond. Mr. David Don. 

 Ben Arthur. Professor Hooker and Mr. Borrer. 



Perennial. June, July. 



Habit very much like the last, but the stems are only half as tall, 

 completely invested with the extremely long, smooth sheaths of 

 the short upper leaves, which, as well as the radical leaves, are 

 firmly involute, and pointed, so as to become awl-shaped. When 

 flattened they are found deeply furrowed on the upper side ; but 

 the back, though bluntly ribbed, is very smooth to the touch. 

 Stipula oblong, bluntish, often torn. P<r«jcte with nearly up- 

 right and close branches, much fewer and less spreading than in 

 A. ccEspitosa. The flowers however are larger, greener, vastly 

 less numerous ; the upper ones, at least in mountainous places, 

 generally viviparous, from the transformation of the spikelet to 

 a bud, on whose first leaves the awns still remain ; see Ensl. 



