100 



NATURALIST'S GUIDE TO THE AMERICAS 



tinental since all the water is frozen 

 over and its modifying effect is negli- 

 gible; but in summer the climate is 

 arctic-oceanic, and even with twenty- 

 four hour sunlight during the summer 

 months, the temperature does not rise 

 high because of the depressing chill 

 off the cold shore waters with their 

 masses of ice. In northern Ellesmere 

 Land the lowest winter temperature is 

 probably —70°; the highest tempera- 

 ture in the interior dales and valleys 

 sheltered from the sea-winds, probably 

 rises to -|- 70°. In the southern portion 

 the temperature does not often drop 

 below —40°, while the interior summer 

 temperatures do not rise far above -t-75°. 

 The precipitation is uniformly light. 

 The rains of summer in the southern 

 portion and the summer snows of the 

 northern part are relatively light. The 

 snowfall over the entire group is not 

 heavy for the entire winter, but the 

 accumulation remains until late May or 

 June, and then the melting furnishes 

 ample moisture for the rapid growth of 

 the vegetation through the short, 

 sunlighted summer. The western coast, 

 facing the prevalent winds receive the 

 maximum precipitation. The first frost 

 comes late in August in the southern 

 portion, earlier in the same month in the 

 northern portion. The ground is frozen 

 throughout the year, except for a thin 

 surface layer a few inches thick that 

 opens up for the short summer. Be- 

 cause of the effect of the twenty-four 

 hour sunlight, and the protracted inso- 

 lation, the "summer" period is approxi- 

 mately the same throughout the whole 

 north and south extent of the archipel- 

 ago. 



BIOTA 



Plant life 



The plant life of the Arctic Archi- 

 pelago has never been thoroughly in- 

 vestigated. The collections are few, 

 far scattered, and incomplete. From 

 none of the islands, except Ellesmere 

 Land perhaps, has even an approach 

 been made to an exhaustive and rep- 

 resentative collection. 



The character of the vegetation is 

 similar to that of Western Greenland, 

 though in the lower, flatter western 

 portions of the archipelago, the bog and 

 moor, or tundra, vegetation spreads 

 over much gi'eater areas, and the "Feld- 

 mark" is relatively more restricted. 

 There are no trees, and few shrubs of 

 any size, most of the vegetation being 

 confined to creeping or dwarfed shrubs 

 and vascular plants — particularly grasses 

 and sedges. 



The paucity of the flora of the Silurian 

 siliceous limestone areas is character- 

 istic, and seems due principally to the 

 lack of fine particles in the detritus 

 resulting from the disintegration of the 

 limestone. There is no true soil; even 

 in the flatter expanses of the Silurian 

 the limestone is riven by frost into sharp 

 angular fragments that do not afford 

 proper foothold for plants or for the 

 absorption and capillary retention of the 

 necessary water supply. The purer or 

 more argillaceous limestones of the 

 other sedimentaries give rise to a more 

 favorable soil, and on this, as on the 

 soil derived from the pre-Cambrian, the 

 vegetation is abundant and more gener- 

 ally distributed, apparently little 

 affected by the composition of the soil. 



The flora, so far as known, is made up 

 of slightly more than 200 species, repre- 

 senting 31 families, of which the largest 

 are the Graminae, Oyperaceae, Oruci- 

 ferae, and Compositae, in the order 

 named. The genera richest in species 

 are Carex with 12, Saxifrag a with 12, Salix 

 with 10, and Pedictilaris with 7. Sixty- 

 two species are distributed throughout the 

 archipelago; 18 species extend over the 

 southern portion; 35 are confined to the 

 south-western islands; 28 species are 

 decidedly western in origin and range; 

 and 23 are distinctively eastern. The 

 proportion of monocotyledonae increases 

 northward. The distribution of these 

 genera and species over the archipelago 

 raises interesting questions of origin, 

 migration, and relationship which have 

 been the cause of much controversy, 

 involving the extent and continuity of 

 the Pleistocene glaciation; former land 



