407 



Flowering takes place in the middle and the end of sum- 

 mer; in Spitzbergen ripe fruit has not been observed (Ekstam, 

 Nathorst); but it can certainly be developed in Siberia (Fig. 

 47, C). — E. PaUasii and the hybrid both grow in moss. 



Geographical Distribution. The hybrid has been 

 found in Spitzbergen only; R. FaUasii in Arctic America and 

 Labrador, Spitzbergen, Arctic Finland, Arctic Russia, Nova Zembia 

 and North Siberia (Nathorst). 



Anatomy. The roots are often very long, filiform, and 

 usually unbranched. Their structure is of the common type 

 and the texture is exceedingly loose. The epidermis and the 

 exodermis were suberized, the latter had undulating walls. A 

 few layers of the cortex remained within the exodermis and 

 a few outside the endodermis, also some slender, radiating 

 trabeculae. The endodermis was suberized, the walls were not 

 thickened. The central cylinder was diarch. A few thin-walled 

 root-hairs occurred. The starch-grains are compound, especially 

 in the inner layers of the cortex. — 1 did not find hyphae in 

 the roots. 



In R. FaUasii the internodes of the horizontal stem and 

 the peduncle (in the flowering period) had a similar structure. 

 The cortex was few-layered and had numerous large intercellular 

 spaces (Fig. 48, C). The epidermis showed a slightly striped 

 and indistinct cuticle, and the outer walls of its cells were thin; 

 the latter contained some chlorophyll. The stomata were on a 

 level with the surface. From seven to eight vascular bundles 

 occurred; in the peduncle they were surrounded by a somewhat 

 greater amount of close-set parenchyma than in the internodes 

 of the stolon. The specimens examined contained neither bast 

 nor lignified parenchyma, but perhaps these are developed in 

 the peduncle during the ripening of the fruit when it stands 

 stiffly erect (herbarium-material). The bundles are arranged 

 very excentrically in the thick stem, and the whole of the pith 

 is broken down (Fig. 48, B). 



