158 



13. ScHROETER, С, 1904—1908: Das Pfianzenleben der Alpen. 



14. Segerstedt, p., 1894: Stud, öfver buskartede stammars skyddsväfnader. 

 Bih. t. K. Sv. V. A. Handl. 19. Afd. 111. No. 4. 



15. Simmons, H. G., 1906: The vascular plants in the flora of Eilesmereland. 

 Report of the second Norwegian arctic expedition in the "Frani". 1898 — 

 1902. No. 2. 



16. Skottsberg, C, 1900: Einige blütenbiologische Beobachtungen in arkt. 

 Teile vom Schwedisch Lappland. Medd. frän Stockholms högskola. No. 210. 



17. Syla'én, N., 1906: Om de svenska Dikotyledonernas första förstärknings- 

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18. Wagner, A., 1892: Zur Kenntniss des Blattbaues der Alpenpflanzen und 

 deren biolog. Bedeutung. Sitzungsber. d. kaiserl. Akad. d. Wissenschaften 

 in Wien. Mat.-naturw. Gl. G. 1. Abth. 1. 



19. Warming, E., 1878: Smaa biologiske og morfologiske Bidrag. Botanisk 



Tidsskrift. 10. 



20. —, 1886—1887: Om Grønlands Vegetation. Medd. om Grønland. XII. 



21. — , 1888: Biologiske Optegnelser om Grønlands Planter. 2. Botanisk 

 Tidsskrift. 16. 



The primary root-system consists of a comparatively strong 

 primary root, sometimes striking deep and branching less 

 abundantly, sometimes striking less deep and freely putting 

 out horizontally-growing roots. Afterwards short, abundantly- 

 branching, adventitious roots proceed from the creeping shool- 

 syslems, but these roots are comparatively few in number. 



Root-hairs are absent. Mycorhizas appear to be rare. 

 Only in a few instances, e. g. in material from Iceland, did 

 I find mycorhizas — short, club-shaped, and with numerous 

 mycelium-threads projecting from the surface. 



In the first period of growth the primary shoot attains 

 only a slight length and remains unbranched; in seedlings 

 collected by C. Б. Ostenfeld at Øtjord in Iceland, on July 30, 

 1886, the epicotyl measured about 7 mm., while the hypocotyl 

 and primary root together measured about 2'5 cm. It is pro- 

 bable that the primary shoot does not branch until the second 

 or third year. 



The lateral shoots of the young plant are transversely 



