BOTANICAL NEWS, 189 



island Mr. "Watson has separated 70, wliich belong by preference to 

 the west side of the island, and constitute what he names the 

 ** Atlantic type of distribution," and 127 species which belong by 

 preference to the east side of the island, and constitute what he names 

 the ''Germanic type of distribution/' In Britain, as we have 

 already explained, the west side is more insular and the east side is 

 more continental in its climate, and difference in climate is in this 

 case intensified in its relation to plant-station by the nature of the 

 subjacent rocks, the chalk and other dry rocks of calcareous nature 

 being mainly concentrated in the eastern half of England, between 

 Sussex, Hampshire, and the Tyne, There can be little doubt that a 

 principal cause of one set of these plants affecting the east and the 

 other the west side of the island is the more Xerophilous constitution 

 of the former, and the more Hygrophilous constitution of the latter 

 group, the two types here, as elsewhere in extra-tropical latitudes, 

 corresponding in the main to the groups which, in their relation to 

 heat, I have called the warm-lovers and cold-fearers. 



In the North of England, and especially in my native county 

 (Yorkshire), we have masses of these dry rocks of calcareous con- 

 stitution, with great belts interspersed between them of strata of 

 other kinds. There are a certain number of plants which follow the 

 dry rock from area to area, and avoid the intermediate belts. In the 

 North Riding of Yorkshire I found that 67 species, or one in thirteen, 

 of the indigenous plants did this more or less decidedly. As instances 

 of such plants I may mention the common Columbine, the Lily of the 

 Valley, the Ely Orchis and Bee Orchis, Helianthemum vulgare, 

 Geranium sanguineum, Sesleria coerulea, Actsea spicata, and Brachy- 

 podiura pinnatum. In the heart of the Continent there are two great 

 hill-ranges of different lithological constitution, the granitic Yosges 

 and calcareous Jura. The late M. Thurmann, ^^ho investigated the 

 subject very carefully, has given an account of what plants are 

 peculiar to each range ; and we find that many species (such as Betula 

 alba, Sarothamus scoparius. Galium saxatile, Hypericum pulchrum, 

 and Stellaria Holostea), which in England are the common product of 

 strata of all kinds, and grow freely upon the same limestone hills to 

 which the Insect Orchids and Columbine are restricted, upon the Con- 

 tinent are absent from the calcareous Jura, and restricted to the 

 granitic Yosges. It would seem that under the more insular climate 

 these plants could grow freely upon soils which they avoid under 

 the continental climate, and that in tliis way the moisture of the air 

 in its relation to plants is modified by the character of the soils in 

 which they grow, and the nature of the great masses of subjacent 

 rock below the immediate surface. 



{From the Gardeners' Chronicle for May 1 5th, 1875.) 



25Dtamcal |3c\d^. 



Articles in Journals. — April. 



Bot. Zeitung. — L. Celakovsky, ''Discussion on the embryo." 

 -J. MuUer, " Keply to Dr. Baillon's ' Xouvelles observations sur les 



