250 



of the species of wliicli the investifjatioii is liere recorded, to 

 l)üint out any anatomical difTerence which characterizes the whole 

 of the one section in contradistinction to tiie whole of the other. 



Saxifraga nivalis L. (Figs. 5 and 6). 



Saxifraga nivalis L. occurs far above the tree-limit in 

 Arctic regions, where (according to Norman) it usually grows on 



Fig. 5. Saxifraga nivalis. 



A (2/i), Leaf-form. B, Hairs from leaf-margin. C, Longitudinal section of leaf with hyda- 

 thode. D, Transverse section of leaf. {B, C, and D '^U). 



sloping ground, three times more commonly on the sunny side 

 than on the shady side ; it usually grows in dry localities, more 

 rarely in damp. M. Porsild informs me verbally that in Green- 

 land it is found among damp moss and upon cliffs wetted by 

 spray. The plant according to my judgement is fairly distinctly 



