WILD PLANTS. 
24 
others being obtainable from the seedsman : this we 
consider as perennial ; yet, let us lay down two pieces 
of land with seeds, from the same sack, the one a low, 
moist, deep soil, the other a dry upland, and in three 
or four years we shall find the natural herbage of the 
country spring up, dispute and acquire in part possession 
of the soil, in despite of the ray-grass sown : in the 
deep soil, the predominant crop will probably consist of 
pose, cockfoot, meadow-fescue, hole us, phleum, foxtail, 
&c. ; in the dry soil it will be dogstail, quaking grass, 
agrostis, &c., not one species of which was ever sown 
by us. It appears that the herbage of our poor thin 
clay-lands is the natural produce of the soil, for every 
fixed soil will produce something, and would without 
care always exclude better herbage. Attention and 
manures, a kind of armed force, would certainly support 
other vegetation, alien introductions, for a time, but the 
profit would not always be adequate. In a piece of 
land of this nature I have suppressed the natural pro- 
duce, by altering the soil with draining, sheep-feeding, 
stocking up, and composting: and scabious, carnation 
grass, mat grass, and their companions, no longer thrive ; 
but if I should remit this treatment, they would again 
predominate, and constitute the crop. 
Most counties seem to have some individual or spe- 
cies of wild plants predominating in their soil, which 
may be scarce, or only locally found in another ; this is 
chiefly manifested in the corn-lands — for aquatic or al- 
pine districts, and some other peculiarities, must form 
exceptions. This may be in some measure occasioned 
by treatment or manure, but commonly must be attrib- 
uted to the chemical composition of the soil, as most 
plants have organs particularly adapted for imbibing 
certain substances from the earth, which may be reject- 
ed 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 de« 
