13] 



VEGETATIONAL TYPES OF POLAR LANDS 



403 



most widespread and often the sole heathy plant, Arctic Bell- 

 heather, may be practically confined to such situations. In the low- 

 and middle-arctic belts the outermost zone of such ' snow-patches ', 

 which is well protected in winter by snow but does not have its 

 growing-season markedly reduced by late melting, is commonly 

 vegetated by a luxuriant mixed heath (Fig. 129), or, in lastingly 

 damp situations, by a thin Willow scrub. Farther in, where 

 the snow drifts sufficiently deeply for the growing-season to be 



Fig. 128. — Purple Saxifrage barren on exposed ridge (nerlooking the sea in 

 northernmost Baffin Island. The Soxifraga oppositifolia agg. forms only scattered 

 tufts and small dark matlets that scarcely show in the photograph; nevertheless, 

 around a prominent boulder that has persistently acted as a perch, there is a 

 luxuriant grassy sward where the ground has been manured. 



appreciably shortened, Arctic Bell-heather characteristically forms 

 a dark belt, often being the sole dominant as in Fig. 118. In 

 other instances this belt may be more mixed and only 1-3 metres 

 wide, as in Fig, 129, which shows in the background the more 

 barren inner zones. These are apt to vary considerably in number 

 and vegetation in different places and circumstances. However, they 

 typically include towards the outside a zone of dwarf Willows 

 (particularly Herb-like Willow, Salix herbacea, as in Fig. 130), 

 and, farther in where the growing-season is too short for woody 

 plants, a sparsely vegetated zone with a considerable variety of 



