PHYSICAL GEOGRAPHY 



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fragilis, but also flowering plants, such as Sedum annuum, O.ryria 

 digyna, Plantago maritima, Saxifraga ccespitosa, Poa glauca, Festuca 

 ovina, and others. On damp rock-faces near large waterfalls these 

 same species are met with, often as large, well-developed specimens 

 (H. Jonsson, 1905, p. 30): also Poa alpina f. viuipara, Aira alpina, 

 Saxifraga hypnoides, S. stellaris, S. n waits, S. ccespitosa and several 



Fig. 31. The river Thvera in Oxnadal. Epilobinm hiti folium and Aim on a small 



gravel-island in the river: July. 1909. 

 (Phot. A. Hesselbo.) 



species of mosses. Nowhere is seen so mixed and variegated a plant- 

 society as on extensive, fairly densely plant-covered mountain slopes 

 where the majority of the plant-formations are met with, in patches, 

 side by side. On a talus of fallen blocks and debris (urd) there is 

 often a considerable vegetation of lichens, mosses and liverworts. 

 In some places, especially far up on the mountains, the sloping 

 heaps of rock-fragments are poor in plants: in other places they 

 carry a rich vegetation of ferns or willows and birch shrubs and 

 heather, with a variable admixture of herbaceous plants from dif- 

 ferent formations, with no special character, the vegetation resembling 

 closely that which occurs in ravines and lava-clefts. 



Where the conditions of life are specially favourable; where the 



