GRASSES OF SCOTLAND. 55 



most northern parts of North America. Its lowest limit of altitude 

 is 3000 feet above the sea. 



Flowers in the first week of August, and ripens its seed in the se- 

 cond week of September. Sheep seldom touch it, as the leaves are 

 generally found entire. 



.37. AlRA FLEXU06A.* 



Wavy Mountain Hair- Grass. 



Specific Characters. — Awn arising from a little above the base of 

 the floret, and extending considerably beyond its summit (Plate 

 XXIV.) 



Description. — It grows from twelve to eighteen inches high. The 

 root is perennial, fibrous, woolly in sandy ground- Stem erect, fiat- 

 tish, smooth, striated, bearing three or four leaves with rougliish 

 (from above downwards) striated sheaths: the upper sheath much 

 longer than its leaf, crowned with a membranous acute ligule. 

 Joints smootL Leaves very narrow, acute, of a dark-green, the radical 

 leaves smooth, long, and numerous ; those of the stem roughish from 

 point to base. Inflorescence compound panicled, of a pale brownish-green. 

 Paniclf erect, the branches spreading, very slender, roughish, tri- 

 ple-forked ; lower part of the rachis and branches frequently wavy. 

 Spikelets erect, oftwo-awned florets, not protruding beyond thecal\-x 

 Cali/x of two nearly equal membranous glumes (Fig. 1), without la- 

 teral ribs, and slightly roughish at the keels. Florets of two paleae, 

 (Fig. 2), the outer palea of lowermost floret bifid at the summit, 

 hairy at the base, with two delicate ribs on each side ; keel roughish, 

 furnished with a slender awn arising from a little above the base, and 

 extending considerably beyond the summit of the palea. Inner palea 

 membranous, ven.- thin, about equal in length to the outer palea, and 

 very minutely fringed at the margins. Second floret elevated on a 

 hairy footstalk, rather smaller than the lower floret, but similar to it 

 in ever}- other respect 



Obs. — Airajiexnosa is distinguished from Aira caryophyllea, in the 

 spikelets being twice as large, and the upper sheaths rough from 



• Aira flcxHOsa, Linn. Smith, Koch. H<3oker, Grcville. 



