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The Naturalist. 



inorganic detritus mixed in equal proportions, lie places the Potentillas, 

 Primulas, Gentians, Orchids, Leguminosae, Umbelliferae, Cyperacese, 

 and grasses. In the third group, which need a soil rich in humus, he 

 places the Junci, Luzulas, Heaths, Vaccinia, Ferns, and Lycopodia. 

 In a second list he classifies the species in three groups, according to 

 whether they succeed best in soil containing lime, or whether lime 

 harms them, or whether they are indifferent to it. Among the lime- 

 lovers he places Campanula pusilla, Cypripediuvi Calceolus, Draba 

 aizoides, Dryas octopetala, Primula auricula, Scabiosa lucida, Ruhus 

 saxatilis, and Phyteuma orbiculare ; amongst the lime-haters he 

 classifies Allosoras crisj)us, dsplenium septentj'ionale, the Broseras, 

 LinncBa horealis, Lycopudimn alpinum and Selago, Viola lutea, Salix 

 Jierbacea, Trientalis europaa, and Scirpus ccespitosus ; ' amongst the 

 species indifferent to lime he places Aspidium Lonchitis, Gentiana verna^ 

 Lychriis alpina, Saxifraga aizoides and stellaris. And, finally, he again 

 classifies all the species under three groups, according as to whether 

 they grow best in a sandy or a clayey soil, and are indifferent in this 

 respect. So that we get a full classification of all the species noted, 

 made from three different points of view, which is eminently suggestive 

 in its bearing upon their dispersion as wild plants. 



We have in the North of England five hill-masses of different and 

 well-marked lithological constitution — the porphyritic Cheviots ; the 

 slate hills of the Lake country ; our great hill-mass of North-East 

 Yorkshire, made up of lias and oolite ; and the great backbone ridge 

 of the Pennine chain, underlaid by limestone grits and shales of 

 carboniferous age. Several years ago I made a calculation* that out 

 of the 201 boreal plants of Britain we had 102 in the North of 

 England, and that out of these, in the Cheviot range there were 38, in 

 North-East Yorkshire 33, amongst the slate hills (which have a 

 damper climate and rise to a higher level than the other three ranges) 

 79 species, and amongst the Pennine chain in the North Riding, 76. 

 I should like to see this contrast between the four hill-masses worked 

 in detail, not for the montane species alone, but also for the plants of 

 the British type, and for those of the English type that reach up 

 amongst the mountains. How is it, then, in Teesdale there is such a 

 nest of mountain plants concentrated within a limited area at a com- 

 paratively low level ? Out of the 100 montane plants of the North of 

 England, ten species are almost or quite restricted to an area of a few 

 square miles in the superagrarian zone in Upper Teesdale — a few 



* On tke distrihution of tke montane plants of the North, of England, in 

 Trimen's Journal of Botany," Sept., 1871. 



