48 CLASS III. ORDER III. 



Much smaller and more slender than the preceding, in its as- 

 pect resembling small spikes of rye. Leaves and sheaths vari- 

 able from smooth to pubescent. Involucre four leaved, deeply 

 nerved, two flowered, one floret commonly abortive. Awns 

 three or four times as long as the corolla. — Woods. — July. — 

 Perennial. 



§ Subgenus Gymnosticum. Involucre uncertain, spikelets di- 

 varicate. 



Elymus hystrix. L. Ilcdgcliog grass. 



Spikes erect; involucre of four bristles or callosi- 

 ties; spikelets in pairs, divergent, at length divari- 

 cate. 



Si/n. AsPRELLA Hystrix, Cavan. 



Gymnostichum Hystrix. Sclircb. 



This singular grass is known at sight by its pairs of diverging 

 spikelets placed almost at right angles with the rachis. It differs 

 from the genus Elymus, in the apparent absence of the invo- 

 lucre. The lower pairs of spikelets, however, have commonly 

 a short setaceous involucre of four bristles springing from the 

 same number of callosities at base. Upwards, the bristles dimin- 

 ish in size and number, leaving only the callosities in their 

 place. Spikelets in pairs, widely divergent, three flowered. 

 Awn three or four times as long as the corolla. — Woods. — July 



By an oversight, the late Dr. Muhlenberg has called the spike- 

 lets six to nine flowered. 



We have two varieties. 



«. Three or four feet high, sheaths smooth, spikelets about 

 twenty, pubescent. 



^. One or two feet high, sheaths rough, spikelets about ten 

 glabrous, 



53. HORDEUM. 

 HoRDEUM JUBATUM. Ait. Squirrcl tail gvass. 



Lateral florets abortive, their awns many times 

 shortest, involucres setaceous, six times as long as 

 the flower. 



