nTEODUCTIOîî. 



A biological-anatomical description of the Arctic species of 

 Saxifraga must essentially have reference to the foliage-leaves, as 

 they are the organs which most distinctly bear the impression of 

 external factors in nature. The roots were less suitable for anatomical 

 investigation in the material which has been within my reach. All 

 the material which I have had for examination has been placed at 

 my disposal by the director of the Botanical Museum in Copenhagen. 



The literature of the subject does not contain much regarding 

 the leaf-anatomy of the genus Saxifraga. Engler was the first to 

 give a more exhaustive account of it in his monographic treatment 

 of the whole genus (Breslau, 1872. See list of literature). He does 

 not ti-eat the individual species anatomically, but confines himself 

 to a kind of comprehensive characterization, without entering more 

 fully into the peculiarities of the different species. The genus is 

 treated in very much the same way by Thoc venin (1890) and Leist 

 (1890). (I have unfortunately been unable to have access to a 

 paper by Waldner (Graz, 1885) on the ''lime-druses" oï the Saxifragas). 



The first three works mentioned above give, therefore, only 

 very scattered data regarding the species we are here considering, 

 and treat them according to systematic principles, without discussing 

 the connection between structure and biological conditions. 



More exhaustive descriptions are given by Leist (1889), Bonnier 

 (1894), Borgesen (1895), Lazniewski (1896). These works aim 

 particularly at elucidating the relation between habitat and anatomical 

 structure, — Leist and Lazniewski with regard to the Alpine. Bor- 

 gesen with regard to the Ai'ctic plants. Bonnier compares Alpine with 

 Arctic specimens of the same species; among the many examples 

 he gives, he mentions only one Saxifraga (S. Aizoon). Freidenfelt 

 (1904) occupies himself with the root-anatomy of a few species, 

 considering them to a certain extent from a biological point of 

 view. Holm (1885) mentions the anatomy of several Arctic species, 



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