FLORA AND FAUNA ON THE NORTH COAST 



claim of life we may thus put aside, but it is worth noticing that vegetation 

 is richer where the ground consists of certain kinds of rock — for instance, 

 limestone, than of others — for instance, ground rock. This, however, is no 

 peculiarity confined to the Arctic regions. 



The second condition of life — heat — is in the Arctic regions present to such 

 a small degree that it becomes of definite significance to the luxuriance of 

 plant growth. We will therefore examine this point more closely, deciding 

 from the outset that plants cannot grow : at temperatures below freezing-point. 

 On the other hand, Arctic plants can put up with being frozen stiff without 

 detrimental effects. Their growth stops, but as soon as they thaw they 

 recommence their growth. Thus Wulff observed (on the 4th of May) a tuft- 

 saxifrage with fully developed flowers on inch-long stalks ; it was quite frozen, 

 the temperature of the air being minus 11° C, but all tissues seemed capable of 

 life, and when spring returned it would, without doubt, directly continue its 

 development. 



On the north coast of Greenland the temperature is above freezing-point 

 only during a short period of the year. At noon on the 30th of May the first 

 positive temperature of the air was observed (plus 0'8 C), and by the end of 

 August the continual frost again sets in. There is thus only a period of at 

 most three months within which the plants have to grow, flower, and fruit, 

 and store nourishment for next year. And how many hours, or even days, 

 within this short time must be subtracted because snow and cold stop the 

 growth ! In the middle of June Wulff wrote in his diary (17th of June) : 

 " The vegetation is yet in its winter repose. The soil is frozen ; the plants 

 which I brought from our previous camp cannot yet be pressed, as the clumps 

 of moss and pieces of soil attached to them are frozen rigid." He is of the 

 opinion that, on the whole, vegetation revives only by the summer solstice, and 

 writes very aptly : " The ' explosive ' development of the Arctic vegetation 

 takes place in a kind of staccato — rapidly during the warm, light hours, and 

 ceases entirely during the many long, cold, windy days of sleet." 



One would think it impossible for plants to manage with so little warmth, 

 but it is sufficient for the most frugal among them. It is a help to them that 

 the soil and the plants themselves are warmed more quickly and to a higher 

 degree than the surrounding air. It is a well-known phenomenon that a 

 dark surface subjected to the rays of the sun becomes warmer than the air ; 

 and in Arctic regions this fact is undoubtedly of great importance for the 

 growth of the plants. 



Similarly to other Arctic explorers, Wulff has repeatedly measured the 

 temperature on various types of ground in order to obtain statistics to illus- 

 trate this point. A few of his results will be given here to demonstrate the 

 various differences : 



May 19th, 2 p.m. — A hill sloping towards the sun. Calm, clear sunshine 

 (McMillan Valley). 



Temperature of the air in the shade minus 11 '8° C. 



The thermometer with its ball of mercury : 



1. On a light-brown, sunny cliff of sandstone : minus 1° C. 



2. On a sunny clump of saxifrage : plus 2'8° C. 



3. In cespitous moss : plus 9'2° C. 



June 20th, 4 p.m. — A slope to the west. Calm, clear sunshine (Chip Inlet). 

 Temperature of the air in the shade plus 5° C. 



293 



