CLIMATIC ZONES 41 



and some lodge-pole pine, mingled with alders, willows, mountain- 

 ash and birch, and various shrubs — spiraea, raspberries, n> 

 and others. A number of pretty flowers were noted — especially 

 an unusual abundance of the dwarf cornel (Cornus Canadensis). 



The summit of the pass marks the timber-line, the spruces being 

 only a few feet high, or forming prostrate mats. In early July, 

 the creeping shoots of the dwarf arctic willow, were adorned with 

 large and conspicuous catkins. 



From the summit, the pass gradually descends to the Lake 

 region at the headwaters of the Yukon. 



This inland region, comprising parts of the Yukon Territory 

 and Northern British Columbia, has a very different climate 

 from that of the coast — relatively dry, and intensely cold in winter, 

 so that the growing season is a very short one. Under such con- 

 ditions it is rather surprising, therefore, to find along the Upper 

 Yukon, a fairly abundant growth of good sized trees, mainly 

 spruce, which furnishes lumber and fire-wood. Along the river, 

 especially in the numerous islands, are groves of tall balsam 

 poplars (Populus balsamifera), associated with thickets of alders 

 and willows. Such forests may be seen as far north as Dawson 

 (lat. 64°). Paper birches of fair size also occur in this region. 

 The wide-spread lodge-pole pine (Pinus Murrayana), sometimes 

 occurs in extensive stands along the Upper Yukon. 



Among the characteristic shrubs, perhaps the most beautiful 

 is a rose (Rosa Nutkana), very common throughout the Yukon 

 country. Other common shrubs are species of Spiraea, Ribes, 

 Cornus and buffalo-berry (Shepherdia). In some places a service 

 berry (Amelanchier sp.) was noted. In the dryer localities a low 

 juniper (J. nana) and sage-brush (Artemisia frigida) may be seen. 



Many references have been made by visitors to these northern 

 regions, to the profusion of showy flowers which adorn the brief 

 summer. Some of these, like species of anemone and saxifrage, 

 flower quickly after the snow melts; but the great majority belong 

 to mid-summer, when they often occur in great numbers. 



A good many of these northern flowers, like the fireweed (Epilo- 

 bium angustifolium), and such woodland flowers, as Linnaea, 

 Pyrola, and the dwarf cornel, are common throughout much of 

 the northern United States and Canada, and the same is true of 

 such trees as the aspens, poplars, and some of the shrubs; but 



