172 Fernald — Relationships of some American 



difference." And in his summary of cliaracteristics, he said : 

 " The White Birch of Europe and the Canoe Birch resemble 

 each other in their wood, their bark, and their ample propor- 

 tions, which are perhaps superior in the American species. 

 The J differ in the form of their leaves, and they grow on very 

 different soils : the Canoe Birch is exclusively attached to rich 

 lands constantly cool, and capable of yielding an abundant har- 

 vest of corn or of clover, and it propagates itself naturally only 

 in that part of JS'orth America which corresponds in climate to 

 the 54th and 55th degrees of latitude in Europe." 



These distinctions pointed out by Alichaux are not, however, 

 of such fundamental importance as to prove the American 

 Canoe Birch {Betula papyrifercC) organically distinct from the 

 White Birch {B. alba, L., B. piihescens, Ehrh.) of Europe. 

 Michaux made no distinction in his Sylva between the true 

 Betula alba and the smooth-leaved and smaller B. pendula, 

 Roth. His plate was of the latter plant, which has more 

 deltoid leaves than the true B. papyrifera, but is quite like 

 another American tree soon to be discussed. The foliage of 

 the true B. alba is, nevertheless, as will be seen on comparison 

 of American and European material, so similar as to present no 

 apparent distinctive feature. The Canoe Birch in its best de- 

 velopment, which Michaux places at a height of TO feet, is 

 found in deep soil on hillsides ; but, had that keen observer 

 been permitted to remain longer in our northern regions and 

 to have explored the upper slopes of our mountains, he would 

 have found the same tree there growing from the crevices of 

 bare ledges — quite as barren a soil as that occupied by the 

 European tree, which, by his own statement, may be 70 or 80 

 feet high. The more southern occurrence of the American 

 tree is at least negative evidence of its identity with the tree 

 of Scandinavia, northern Germany and Russia, for, as is now 

 well known, the isotherms which cross New England pass far 

 to the north in Europe, and the vegetation of northern New 

 England and adjacent Canada has more than once been com- 

 pared with that of Scandinavia. In fact, Michaux himself, in 

 discussing the range of the Canoe Birch, said : " This part of 

 North America, though situated 10 degrees further south, very 

 nearly resembles Sweden and the eastern part of Prussia, 

 not only in the face of the soil, but in the severity of the 

 climate." Thus the comparative notes of Michaux leave little 

 by which to distinguish the American from the European tree ; 

 and it is further worthy of note that in Boswell Syme's enu- 

 meration of the uses of the bark of the European tree he says : 

 " In Russia it is applied to the same purposes for which that 

 of the Canoe Birch is used in North America, boats being 

 formed of it that are nearly as light and portable as those made 



