384 



and divided to the base into 3—5 lanceolate-oblong segments. 

 This variety grows in mossy bogs and often together with the 

 principal form. Hartz found numerous transitional forms be- 

 tween the variety and the principal form (1, p. 52). Nathorst 

 found this variety on Disco, where Hartz also found it as he 

 also did on Arveprinsens Island. 



In var. Langeana il often happens that the internodes of 

 the rosettes are elongated, in correspondence to its life in 

 quickly-growing moss. 



Geographical Distribution. West and East Green- 

 land, Iceland, Scandinavia, Beeren Eiland, Spitzbergen, Nova 

 Zembla, Arctic Russia, North Siberia, Arctic North America, 

 the Rocky Mountains (Lange, Тя. Holm). 



Anatomy. The root of the first order was diarch or triarch. 

 The epidermis was more or less collapsed especially in roots of 

 the second order. The exodermis was distinct, the latter and 

 the epidermis were suberized. The outermost layers of the 

 cortex were either not at all coUenchymatously thickened or but 

 very slightly; its intercellular spaces were fairly large ; lysigenous 

 lacunae often occur, especially in roots of the second order. 

 The endodermis was suberized but not thickened. 



Mycorrhizas have been found in specimens from Advent 

 Bay, Trondfjældet and Disco. The hyphæ often form balls in 

 the inner cortical layers, especially in roots of the second order. 



The greater part of the epidermis of the rhizome had 

 fallen off in the specimens investigated; the outer cortical 

 layers were suberized and slightly thickened. Lacunae were 

 absent from the cortex. 5 — 8 vascular bundles which anasto- 

 mosed freely were present; and also, in different sections of 

 the same root, isolated bundles were seen with a special endo- 

 dermis; also groups of bundles, each group with its own 

 endodermis; or else all the bundles were fused together so that 

 there was an outer and an inner endodermis, between which 

 the bundles occurred (Fig. 31, Л). The cambium was rudimen- 

 tary. The vessels were scattered among non-lignified paren- 



