184 Fernald—Relationships of some American 
than is occasionally seen in B. alba (B. papyrifera) in the 
Northeast and already mentioned in the discussion of B. oeci- 
dentalis. The color of the bark, then, furnishes no satisfac- 
‘tory reason to separate Betula kenaica from the Asian 8. 
pendula, var. japonica. 
Betula pendula (typical). 
The broad-leaved var. japonica is not the only form of 
Betula pendula which crosses from Europe and Asia into 
North America. As already noted; the typical European £. 
pendula with leaves cuneate at base extends across northern 
sia. Some of the specimens which have been referred to 
B. alaskana are quite inseparable in their leaves, branches, 
and strobiles from European specimens; and, furthermore, 
this characteristic European form extends southward and east- 
ward in America to western Illinois, the Great Lakes, and the 
St. Lawrence Valley. Sheet No. 351,017 of the United States 
National Herbarium, collected as B. ulifolia in woods at 
Warren, [linois, by L. M. Umbach, is not distinguishable from 
sheet No. 25,340 from Sungaria in central Asia, nor from 
material in the Gray Herbarium collected in Sweden (lom- 
berg, No. 1,691). Sheet No. 261,119 of the U. S. National 
Herbarium, collected by Professor James Fowler in Ontario as 
B. populifolia, has the strobiles and leaves of B. pendula and 
it cannot be separated from material in the Gray Herbarium 
from Christiania, Norway (Blytt), and from St. Petersburg, 
Russia (2egel). A sheet in the Herbarium of the Geological 
Survey of Canada (No, 12,950), collected in the Province of 
Quebec as B. populifolia by W. Scott, is quite identical with 
sheet No. 149,801 of the U.S. Nat. Herb. from Savoy. Vari 
ous other leaf-specimens from Quebec, Manitoba, and other 
regions of temperate North America are probably B. pendula, 
but without fruit it isat present unwise so to refer them. The 
American specimens cited were gathered as the endemic Betula 
populifolia, at least one of them in “woods”; and_since 
undoubted B. pendula is found from the Saskatchewan Plains 
northward, there seems little question that the European tree, 
crossing Asia, is truly indigenous likewise in the northeastern 
sections of America, just as are Coptis trifolia, Drosera 
rotundifolia, Viburnum Opulus, Lysimachia thyrsifiord, and 
many other well known species* which occur in northern 
Europe, central and northern Asia, Japan, northwestern Amer- 
ica, and northeastern America. 
* Among them Caltha palustris, Viola Selkirkii, Parnassia palustris, 
Potentilla palustris, Circaea alpina, Pyrola minor, Moneses grandiflora, 
_ Menyanthes trifoliata, Rumex persicarioides, Allium Schoenoprasum, Juncus 
sus, Eriophorum gracile, Carex filiformis, Hierochloe borealis, etc., et. 
Gray, Mem. Am. Acad., n. s., vi, 377-499: and Extract ‘‘ Flora f 
Japan in Sci. Pap. of A. Gray, selected by C. S. Sargent, ii, 124-141. 
