13] VEGETATIONAL TYPES OF POLAR LANDS 415 



equatorial side ; or else they may be narrow on one side, or dis- 

 continuous, or merely partial. Moreover as they usually merge only 

 gradually into one another, such vegetational zones are often difficult 

 to distinguish unless they are in full development. 



Antarctic Types 



The vegetation types of antarctic and adjacent regions have become 

 sufficiently known in recent years for the broad generalization to 

 be made that they are reasonably comparable with those of the 

 Arctic, even if there is a tendency towards more tussock formation 

 and less woody plants in the South. They also tend to be treeless 

 to much lower latitudes ; in conformity with our delimitation of 

 the Arctic, these treeless regions and their vegetation will be con- 

 sidered here as more or less antarctic, even though many of the 

 islands lie far from the Antarctic Continent and are commonly 

 referred to as subantarctic. Although the floristic composition is 

 largely different, the antarctic flora being in general very limited 

 and widely peculiar, with often a high degree of endemism, plant 

 communities in low-antarctic regions often look much like those 

 developed in the Arctic under comparable circumstances in similar 

 situations. Furthermore, much the same range of vegetation-types 

 is found in the Antarctic and Subantarctic as in the Arctic, whose 

 plant communities we have described and illustrated sufficiently 

 above. Consequently a very general account of the main antarctic 

 and subantarctic types should suffice. In this it should be recalled 

 that antarctic and subantarctic lands are for the most part widely 

 scattered, often being extremely isolated and having extraordinarily 

 limited floras, which in the case of the ice-free portions of the 

 Antarctic Continent consist almost entirely of lowly cryptogams. 



The Antarctic is a very bleak and stormy region possessed of two 

 main climatic areas. The northern one may be described as sub- 

 antarctic and is maritime, with warmer winters and cooler summeis 

 than much of the Arctic, and powerful winds throughout the year. 

 There is heavy precipitation in the form of snow or rain, and little 

 distinction between the seasons. The subantarctic islands have this 

 climate. The other, southern and central region is extremely cold 

 and stormy, having a continental climate without summer warmth. 

 Thus on the entire Antarctic Continent there is scarcely any place 

 having the mean of the warmest month of the year above 0° C. 



In contrast to the Arctic, which apart from ice-caps is largely 



