284 



in many places (in spirit- material), large sphaerocrystals (the 

 composition of which has not been more closely investigated) 

 among the cells immediately beneath the epidermis (Fig. 27). 

 Sphaerocrystals also occur here and there in the epidermal cells. 

 In none of these places — as far as I could judge from living 

 material — do these crystals occur in connection with living 

 cells; they are probably an alcoholic precipitate. 



The veins are accompanied by bundle -sheaths containing 

 tannin (Fig. 26). Each tooth of the leaves is provided with a 

 vein which terminates in a hydathode with a large cavity (Fig. 

 25). The epidermis of the hydathode has 1 — 2 water-pores and 

 some of the cells are elongated as papillae. Lime is abun- 

 dantly secreted — much more abundantly than in S. Cotyledon. 



I have investigated specimens from Kobbefjord (June 29, 

 1884), Holslensborg (July 17, 1884), Sarfanguak (July 15, 1884) 

 in West Greenland, from Ryder's expedition to Scoresby Sound 

 (July 28, 1887), and from Vatnsdal (Aug. 6) in Iceland. They 

 were all almost identical; only the specimen from Sarfanguak 

 had more ample lime-incrustations upon the hydathode than 

 had the rest. 



The plant grows usually in dry localities (part of my mate- 

 rial came from sunny southern slopes); its whole character is 

 rather decidedly xerophytic ; but here also reference should be 

 made to the occurrence of stomata upon the exposed parts of 

 the leaf, as in S. Cotyledon. 



Leist (1889) maintains that in Alpine districts this and the 

 former species have a leaf-structure which more closely resem- 

 bles that of shade -leaves. Lazniewski (1. c.) disputes this, and 

 maintains that the Alpine Saxifraga are xerophytes. — It 

 must be owned that Leist"s assertion carries no conviction, as 

 the necessary figures are wanting, and the descriptions are, by 

 themselves, unsatisfactory. 



