58 GRASSES OF SCOTLAND. 



mostly smooth. Spikelets of two awned florets, both enclosed within 

 the calyx. Calyx of two equal acute glumes, (Fig. 1), without la- 

 teral ribs, minutely toothed on the keels. Florets of two palese, 

 vFig. 2) ; the outer palea of lowermost floret bifid or somewhat beak- 

 ed at the summit, hairy at the base, roughish on the back ; obscurely 

 five-ribbed ; furnished with a long, slender, rough awn, arising from 

 a little above the base, and extending about half its length beyond the 

 summit of the palea. Inner palea membranous, about equal in length 

 to the outer palea, and very minutely fringed at the margins. Second 

 floret elevated on a short smooth pedicle, but in other respects similar 

 to the floret below. 



Obs, — Air a precox is sometimes with difficulty distinguished from 

 Aira caryophyllea, but may be at all times known by the panicle being 

 close, not exceeding half-an-inch in width ; calyx rather acute at 

 the base ; — whereas A. caryophyllea is generally a taller plant, with 

 much smaller spikelets. Panicle spreading, seldom less than an inch 

 in width. Calyx somewhat rounded at the base. 



An early grass of little value ; the leaves soon dry up. Found on 

 sandy hills and wall tops. Occasionally met with in Scotland, but 

 not common ; more frequent in England and Ireland. Found in 

 Germany, France, Italy, and North America, but not known in Lap- 

 land. Its limit of altitude is about 1500 feet above the sea. 



Flowers in the last week of May, and ripens its seed by the end of 

 June. 



40. Arrhenatherum avenaceum.* 

 Oat-like Soft- Grass. 



There is but one species of this genus known. (Plate XXV.) 

 Description. — It grows from two to three feet high. The root is 

 perennial, fibrous, sometimes bulbous. Stem erect, round and 

 polished, bearing four or five leaves with striated mostly smooth 

 sheaths ; the upper sheath much longer than its leaf, smooth, some- 

 times roughish, crowned with a small obtuse ragged ligule, Joijits 



* Arrhenatherum avenaceum, Lindlcy, Hooker. Arrhenatherum clatior, Roch. IIol- 

 cus aienaceus, Smith, Hooker, Fl Scot. Grevil'e. 



