HORTICULTURAL JOURNAL. 301 



(sand sedge,) the roots of which plants bind the shifting sands together. The 

 beautiful sea pink spreads itself over the loose downs — while further inland, 

 and as the soil changes, new vegetable races appear. 



The peaty hills and flats of our island naturally clothe themselves with 

 the common ling, (Oalluna vulgaris,) the fine-leaved heath, [Erica cinerea,) 

 and with the cross-leaved heath, (Erica tetralix.) When drained and laid 

 down to grass, or when they exist as natural meadows, they produce one 

 soft woolly grass almost exclusively — the Holcus lanatus. After they are 

 limed, these same soils become propitious to green crops and produce much 

 straw, but refuse to fill, the ear. The grain is thick-skinned, and therefore 

 light in flour. There is a greater tendency to produce cellular libra, and 

 the insoluble matter associated with it, than the more useful substances, 

 starch and gluten. 



On the margins of water-courses in which silica abounds the mare's tail 

 (Eguisetum) springs up in abundance; while, if the stream contains much 

 carbonate of lime, the water-cress appears and lines the sides and bottom 

 of its shallow beds, sometimes for many miles from its source. 



The Cornish heath (Erica vagans) shows itself rarely above any other 

 than the serpentine rocks; the red broom-rape, (Orobanche rubra,) only on 

 trap or basaltic rocks ; the Anemone Pulsatilla on the dry banks of chalky 

 mounds, as in the neighborhood of Newmarket ; the lady's slipper on calca- 

 reous formations only ; the Medicago lupulina on soils which abound in 

 marl ; while the red clover and the vetch delight in the presence of gypsum, 

 and the white clover in that of alkaline matter in the soil. 



So the red and white fire-weeds, Epilobium coloratum i and Ericlitites 

 Merecifolius, cover with their bright blossoms every open space in North 

 American woods, over which the fires, so frequent there, have run during 

 the previous year. The ashes of the burned trees and underwood are spe- 

 cially grateful to the seeds of these plants, which in vast quantities lie dor- 

 mant in the soils. 



The clays, too, have their likings. The Rest harrow, [Ononis arvensis,) 

 delighte in the weald, the gault, and the plastic clays, but passes by the 

 green-sand and chalk-soils, by which these clays are separated from each 

 other. The oak, in like manner, characterizes the clays of the weald ; 

 while the elm flourishes, in preference, on the neighboring soils of green- 

 sand formation. 



Then, again, plants seem to alternate with each other on the same soil. 

 Burn down a forest of pines in Sweden, and one of birch takes its place for 

 a while. The pines after a time again spring up, and ultimately supersede 



