PHYTOGEOGRAPHY OF GREENLAND 



293 



Fig. 5. Above: North Atlantic areas of a number of species forming the fioristic 

 boundary in Greenland (Sihbaldia prociimbens (without hatching), Fhleiim 

 commutatum (dotted area), Leiiconhis albida (vertical hatching), Alchemilla 

 filicaiilis (horizontal hatching), and A. alpina (oblique hatching)). Below: North 

 Atlantic area showing the annual isohyet 250 mm (broken line), and lines for mean 

 annual temperature range of IS'^C (southernmost full line) and 25°C (northern- 

 most full line). Dotted line indicates the 10°C. July isotherm. Continental Arctic 

 area indicated by hatching and dotting. (From Bocher, 1954.) 



boundary. In this situation the boundary previously mentioned, between a 

 flora which is mainly montane (connected with humid mountains south of the 

 true Arctic areas) and a true Arctic flora (connected with the dry Arctic areas), 

 seems to be much more significant. The northern limit of sylvicolous Boreal 

 plants such as Coptis, Pyrola minor, Platanthera hyperborea, Deschampsia 

 flexiiosa, Chamaenerion angusti folium, Cormis suecica, and some of the 

 montane Sub-Arctic or Low Arctic species, e.g. Alchemilla alpina, Angelica, 

 Gnaphalium norvegicum, etc., gives a much more interesting boundary line, 

 u 



