246 HORTUS GKAMINEUS VVOB U R N ENSl S. 



aruiido arenaria ; the latter, with its tufty habit of growth, 

 formed the summit of the hill, while the broad spreading 

 roots and leaves of the elymiis areiiarius secured the base 

 and sides. These two grasses, when combined, seem admir- 

 ably adapted by nature for the purpose of forming a barrier 

 to the encroachment of the sea. What sand the arundo 

 arenaria arrests and collects about itself, the elymus 

 arenarius secures and keeps fast. The culms are produced 

 in small number when cultivated on a clayey loam, or on 

 a sandy soil. This deficiency of culms was even apparent in 

 the plants, when growing in their natural soil. A greater 

 proportion of saccharine matter is afforded by the culms of 

 this grass than by the leaves. 



Flowers about the third week in July. 



ELYMUS geniculatus. Knee-jointed Lyme-grass. 



Specific character : Spike bent perpendicularly downwards, 



loose ; calyx bristle-shaped, spreading, longer than the 



spikelets ; leaves sharp-pointed. 

 Obs. — A singular habit of this grass is, that the spike, 



just before flowering, bends down by the assistance of 



a joint near the foot of the spike-stalk. 

 Native of Britain. Root perennial. 

 Experiments. — At the time of flowering, the produce from 



a sandy loam is 20,418 lbs. per acre. 



The root is powerfully creeping, and the foliage is tough 

 and coarse. The quantity of nutritive matter it affords is 

 not considerable. It seems, therefore, to be but little 

 adapted for useful purposes. Sir J. E. Smith, in the 

 English Botany, informs us, that it was discovered in the 

 salt marshes of Gravesend by Mr. Dickson, and that 

 Mr. Curtis was the first to distinguish it from the elymu» 

 arenarius, — as it seems even Linnaeus had confounded 

 them. 



At the time of flowering, the produce of the eli/mus 

 arenarius on a clayey loam is 43,572 lbs. per acre. 



This species is greatly sujierior to the above in produce 



