WILD PLANTS. 25 



culiarities, must form exceptions. This may be in 

 some measure occasioned by treatment or manure, 

 but commonly must be attributed to the chemical 

 composition of the soil, as most plants have organs 

 particularly adapted for imbibing certain substances 

 from the earth, which may be rejected or not 

 sought after by the fibrous or penetrating roots 

 of another. Festuca sylvatica abounds in every soil 

 without an apparent predilection for any one : F. 

 uniglumis, only where it can imbibe marine salt : 

 F. pinnata, is found vegetating upon calcareous 

 soils alone, and I have known it appear immediately 

 as the limestone inclined to the surface, as if all 

 other soils were deficient in the requisite nutri- 

 ment. Many of the maiden-hairs and ferns, pelli- 

 tory, cotyledon, &c. are attached in the crevices of 

 old walls, seeking as it were for the calcareous 

 nitrate found there, this saltpetre appearing essen- 

 tial to their vigour and Health. The predomi- 

 nating plants in some corn-fields is the red-poppy, 

 cherlock (sinapis arvensis), mustard (sin. nigra.), 

 wild oat, corn-flower (cyanus) ; but in some adjoin- 

 ing parish we shall only sparingly find them. With 

 us in our cold clay-lands we find the slender foxtail 

 grass (alopecurus agr.) abounding like a cultivated 

 plant: when growing in clover, or the ray-grass, 

 the whole are cut together, and though not a 

 desirable addition is not essentially injurious ; but 

 vegetating in the corn, it is a very pernicious weed. 



