Chap. I] CHARACTERS OF THE ARCTIC CLIMATE 67s 



warm season depends on the circumstance that they are already initiated, 

 and completely differentiated (Fig. 401), in the preceding vegetative season, 

 so that the first warm rays of the sun have only to supply the necessary 

 energy for the elongation of the parts. 



Bunge states 1 regarding the awakening of vegetation in Ssagastyr : ' On the 

 morning of the 28th of May, 1883, the temperature rose above freezing-point for the 

 first time after 250 days of continual frost. On the 29th of June I found the first 

 plants in flower, Chrysosplenium, Draba, and Rhododendron (?).' 



Regarding Fort Conger it is stated' 2 : ' On the 1st of June Saxifraga oppositifolia 

 came into flower, three days later the catkins of Salix arctica flowered, next day 

 Oxyria reniformis, on the nth of June Cochlearia nudicaulis, and on the 21st 

 Papaver nudicaule.' 



In spite of the shortness of the vegetative season there are not wanting 

 species, even in the extreme arctic flora, that, long before the end of the 

 short summer, have terminated their cycle of activity by producing ripe 

 seeds. Thus, in Taimyr, according to Middendorff, Ranunculus nivalis 

 and Androsace septentrionalis had ripe fruits by the 27th of July, and the 

 flowers of Sieversia glacialis had already wilted on the 10th of July, although 

 this plant is not among the first to become active, but had awakened from 

 its winter sleep only three weeks before. Kjellman mentions as species of 

 plants producing ripe fruits quite early, Chrysosplenium alternifolium (end 

 of July), Caltha palustris, Ranunculus pygmaeus, R. nivalis, and Cardamine 

 bellidifolia (August). 



An account of the climatic conditions of existence of the vegetation in 

 North Siberia (Taimyr) is given by Middendorff 3 as follows: — 



' On the 10th of May, for the first time the temperature at noon rose, reaching three 

 degrees above freezing-point ; yet up to the end of the month these warm days alter- 

 nated with a great number of cold days, on which the temperature at noon remained 

 7-5° R. below zero. Up to the middle of June, there was still a minority of days on 

 which there were 2 of frost at midday. Summer began only from the middle of 

 June ; for from that time onwards, throughout July and August up to the first days of 

 September (new style), the air in the shade was always above freezing-point, so that 

 the average temperature of June was 1-5° R., that of July 7-5° R., of August 8-5° R., 

 but that of September already nearly - 1-5° R. 



iii. GROWTH AND METABOLISM OF THE VEGETATIVE ORGANS. 



Low and even stunted growth is the common feature of arctic vegeta- 

 tion. Trees near the tree-limit, before entirely ceasing, are reduced to 

 miniature forms, and the shrubs and herbs of the tundra, except in 

 sheltered places, rise above the ground to a height scarcely equalling the 



1 Bunge, in Meteorol. Zeitschr., 1890, p. 216. See climatic table on p. 670. 



2 Id., p. 17. See climatic table on p. 667. 3 Middendorff, op. cit, p. 656. 



X X 2 



