32 



OUTLINE OF PLANT GEOGRAPHY 



Much of the region is a desolate barren stony formation, whose 

 sole vegetation is made up of various lichens growing on the broken 

 rocks. 



The Behring Sea tundra district is only imperfectly known; 

 but Kjellman l has described 221 species from this district. Of 

 these 53 do not extend far westward, and comprise a number of 

 peculiar species. Others are supposed to have come from the 

 American side of Behring Sea, and some may have been immi- 

 grants from the Baikal Mountains. Two genera also charac- 



Fig. 2. — Tundra, basin of Ikpikpuk River, North Alaska. 

 Photo., Dr. Philip S. Smith. 



teristic of western America are Claytonia and Dodecatheon, the 

 " shooting star" of our Pacific Coast. 



The western Alaska coast is much milder than corresponding 

 latitudes on the Asiatic side, and the vegetation less pronouncedly 

 arctic in character, although the northern part of Alaska shows 

 climatic conditions comparable to those in Siberia. Spruces 

 (Picea alba), alders and willows, extend to the polar circle, and form 

 thickets of considerable extent, while the display of flowers is 

 described as very remarkable. These comprise the usual arctic 

 species, as well as species of spring beauty (Claytonia), forget- 



1 Drude, loc. cit., p. 356. 



