2lii') GRASSES OF BRITAIN. 



AiRA c^spiTOSA (variety) brevifoi.ia. 



Short-leaved Tufted Hah^- Grass. 



Plate CVI. 



This variety of Aira ccBspitosa is found growing near the summit 

 of some of the highest mountains in Scotland, between 3000 and 

 4000 feet above the level of the sea. It is principally distinguished 

 by its short radical leaves, smooth sheaths and stem, small panicle, and 

 dark chocolate colour spikelets tipped with white. The root is peren- 

 nial, fibrous, tufted, producing seldom more than one stern, which 

 is usually about a foot in length, perfectly smooth. The sheaths 

 long and smooth. Leaves short, flat, (usually folded, especially 

 those of the root,) acute, rough, harsh, and strongly ribbed on 

 the inner surface, nearly smooth behind. Ligules prominent, acute. 

 Rachis and branches rough. Spikelets rather large, composed of two 

 glumes and two awned florets, with the footstalk of a third floret. 

 Glumes nearly of equal lengths, acute ; the upper glume three-ribbed, 

 the lower without lateral ribs. Lowermost ^ore^ rather shorter than 

 the lower glume, jagged or toothed at the summit, hairy at the base, 

 bearing a rough slender awn arising from a little above the base and 

 not extending beyond the summit of the palea, (Fig. 3.) Second 

 floret the same as the first, except being raised on a long hairy foot- 

 stalk about one-third the length of the floret. Styles short, distinct. 

 Stigmas prominent, feathery. Filaments slender. Anthers notched 

 at each end. 



It is distinguished from the preceding variety in the whole plant 

 being smaller ; the leaves shorter ; aums of the florets not extending 

 beyond their summits ; and the second Jloret but slightly projecting 

 beyond the glumes. 



It is likewise distinguished from Aira alpina in the awn arising 

 from a little above the base of the floret instead of above the centre. 



From Aira jlexuosa in the sheaths being quite smooth to the touch, 

 and the aums not projecting beyond the summits of the florets ; — 

 whereas in Aira Jlexuosa the sheaths are rough (from above down- 

 wards,) and the awns of the florets extend about one-third their 



