GREENLAND FLOWERS 65 



regions in more southern latitudes. It is an inter- 

 esting fact that Phyllodoce does not occur on the 

 Swiss Alps. 



Cassiope tetragona is a dwarf Arctic shrub of an 

 exceptionally wide high Arctic range; it occurs 

 on the north-west coast of Greenland and extends 

 a considerable distance along the west coast, but 

 does not reach Cape Farewell; it is also met with 

 along a strip of the northern part of the east coast. 

 This species is widely distributed in Spitsbergen ; 

 it is unknown in Iceland, but grows on the northern 

 Scandinavian mountains, and extends along the 

 whole of northern Siberia, crossing the Behring 

 Strait to Alaska, continuing thence along the 

 northern boundary of the American Archipelago, 

 spreading to the south-east along the more northern 

 ranges of the Rocky Mountains to Hudson Bay, 

 and for a considerable distance along the east 

 coast of the North American continent and Baffin 

 Bay to the eastern regions of the United States. 

 Professor Rikli 1 , who has published a very useful 

 map of the geographical distribution of this and 

 other species of Cassiope^ believes that Cassiope 

 tetragona began its wanderings in east central Asia. 



1 The following papers by Dr Rikli of Zurich contain much 

 useful information on the distribution of Arctic flowering plants: 

 Uber Cassiope tetragona (L.) D. Don., Engler's Botanische 

 Jahrbucher, Bd. L (Supplement), p. 268, 1914; Die den 80 N. 

 erreichenden oder uberschreitenden Gefasspflanzen, Fiertel- 

 jahrsschrift der naturforschenden Gesellschaft in Zurich, LXII, 169, 

 1917; Die Arktisch-subarktischen Arten der Gattung Phyllodoce, 

 Vierteljahrsschrift (Zurich), LXVI, 324, 1921. Other references 

 to literature are given in Mr Holttum's paper quoted in the 

 footnote on page 30. 



