56 GRASSES OF SCOTLAND. 



above downwards ; — whereas in A. caryophyllea the spikelets are very 

 small, and the sheaths rough from below upwards. 



This grass grows on heaths and hilly places, and is sometimes found 

 at an elevation of 3500 feet above the sea. It does not thrive on a clayey 

 soil. Sheep eat it, but is not recommended for cultivation. It abounds 

 in England, Scotland, and Ireland ; also found in Lapland, Norway, 

 Sweden, Germany, France, and Italy, as well as in the middle and 

 most northern parts of North America. 



Flowers in the first week of July, and ripens its seeds in the mid- 

 dle of August. 



38. AiRA CARYOPHYLLEA.* 



Silver Hair- Grass. 



Specific Characters. — Awn longer than the palea, arising from a 

 little beneath the middle. Panicle spreading. (Plate XXIV.) 



Description. — It grows from six to twelve inches high. The root 

 is annual, fibrous. Stem erect, round, smooth, and striated, bearing 

 three or four leaves with striated roughish sheaths (the roughness is 

 mostly on the upper half, arising from minute spicula with their 

 points directed dowmvards) ; the upper leaf much longer than its 

 sheath, crowned with a prominent acute ligule. Joi7its smooth. Leaves 

 mostly all on the stem, short, narrow, roughish to the touch. In- 

 fiorescence compound panicled, of a silvery grey. Panicle erect, the 

 branches spreading occasionally zig-zag, but not wavy, slightly 

 roughish, triple-forked, often tinged with purple ; rachis smooth. 

 Spikelets small, rounded at the base, and somewhat tumid ; of two 

 awned florets not protruding beyond the summit of the glumes. Calyx 

 of two equal membranous glumes, (Fig. 1), without lateral ribs, 

 slightly toothed at the keels. Florets of two paleee, (Fig. 2), the outer 

 palea of lowermost floret bifid or somewhat beaked at the summit, 

 hairy at the base, without lateral ribs, furnished with a slender awn, 

 arising from a little beneath the centre, and extending about half its 

 length beyond the summit of the palea. Inner palea membranous, 



* Aha caryophyllea, Linn. Smith, Hooker, Grcvllle, Lindley. 



