LIST OF TREES AND SHRUBS. 311 



As the Kolushes north of Sitka use birch-bark canoes, I infer 

 that this tree extends to the Pacific ; but I have not seen it in the 

 lists of plants of that coast. Pursh mentions Hudson River as its 

 southern limit ; and Gray states its range as extending from New 

 England to Wisconsin, but chiefly through the northern parts of 

 that district. It grows in Nova Scotia, Newfoundland, and 

 Labrador. B. occidentalis occurs in Oregon, along the Rocky 

 Mountains, northwards to the straits of Da Fuca, and crosses the 

 ridge to the vicinity of Edmonton House, on the 54th parallel. 

 B. excelsa, yellow birch, was not traced by us beyond the banks 

 of the Kamenistikwoya, which falls into Lake Superior. In 

 the Northern States it is a stately tree, 60 feet in height. B. 

 lenta, cherry or sweet birch, is a rather large tree, which is 

 common in the Northern States, Nova Scotia, Canada, and 

 Newfoundland ; but does not appear to go far westward, as it 

 was not found by us nor by Agassiz on Lake Superior. B. 

 pumila vel glandidosa, little birch, is rare in New England, but 

 grows in bogs of the northern parts of Pennsylvania, Ohio, 

 Michigan, and Wisconsin ; also in Nova Scotia, Canada, New- 

 foundland, and Labrador. It goes considerably beyond the 

 arctic circle, being found on the banks of the Thlewee-choh, 

 the Coppermine river, and other arctic streams, and also on 

 the Mackenzie to about the 68th parallel. It is very like the 

 following, but has a more erect and slender growth, which 

 may be perhaps owing to locality. The leaves are generally 

 longer. B. nana, dwarf birch, exists on the summits of the 

 White Mountains of New Hampshire, and of the Essex Moun- 

 tains of New York. It grows also in the higher parts of La- 

 brador and Canada, along the shores of the Arctic Sea, from 

 Davies' Straits to Kotzebue Sound ; and generally through- 

 out the Barren Grounds. Alnus viridis, green or mountain 

 alder, and A. incana, speckled or hoary alder, range northwards 

 to the delta of the Mackenzie on the 68th parallel, and from 

 Newfoundland and Labrador to Kotzebue Sound ; the first 

 species being also found on Sitka. They are common bushes in 

 New England and Wisconsin ; but I have not seen their southern 

 limits mentioned. A. rubra, red alder, is an inhabitant of 



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