23J: GRASSES OF BRITAIN. 



AiRA c.^spiTOSA (variety) longiaristata. 

 Long-cacncd Tufted Hair-Grass, 



Plate CV. 



This variety is principally distinguished in the awn of the outer 

 palea extending one-fourth of its length beyond the summit of the 

 palea, and the spikelets of a dark chocolate colour, with a shade of 

 purple tipped with white ; the sheaths and back of the leaves smooth ; 

 in most other respects it is similar to the preceding. It is found oc- 

 casionally on some of the mountains in Perthshire between three and 

 four thousand feet above the level of the sea. The root is perennial, 

 tufted, throwing out two or three stems from a foot to eighteen inches 

 in length. Stems and sheaths perfectly smooth. Ligules prominent, 

 acute. Leaves of the stem smooth behind, rough on the inner sur- 

 face. Rachis and branches roughish, spreading while in flower. 

 Spikelets of two, rarely three, florets. Glumes rather unequal, acute, 

 roughish on their keels ; lower glume the shorter ; upper glume three- 

 ribbed. Lower floret equal in length to the small glume, jagged on 

 the summit, hairy at the base, without lateral ribs. Second floret on 

 a long hairy footstalk, about half the length of the floret. Both flo- 

 rets awned. Aicn arising from a little above the base of the outer 

 palea, and extending about one-fourth of its length beyond the sum- 

 mit of the floret, (Fig. 3.) Styles short. Stifjmas prominent and 

 feathery. Filament slender. Anthers notched at each extremity. 



This grass is distinguished from Airajlexuosa^ the only grass it is 

 likely to be confounded with, in the leaves being flat ; sheaths smooth ; 

 second floret extending beyond the summit of the large glume ; foot- 

 stalk of the second floret about half the length of the floret ; — whereas 

 in Aira Jlexuosa the leaves are round ; the sheaths roughish from 

 above downw^ards ; second floret not extending beyond the large 

 glume ; footstalk of the second floret not more than one-fifth the 

 length of the floret. 



