126 ESSAYS. 
Eastern North American representatives, about 0.61 per 
cent. ; of identical species, 0.23. 
So geographical continuity favors the extension of identical 
species ; but still eastern North America has more in common 
with Japan than western North America has. 
The relations of this kind between the floras of Japan and 
of Europe are obvious enough; and the identical species are 
mostly such as extend continuously — as they readily may — 
throughout Russian Asia, some few only to the eastern con- 
fines of Europe, but most of them to its western borders. To 
exhibit more distinctly the features of identity between the 
floras of Japan and of North America, and also the manner 
in which these are distributed between the eastern and west- 
ern portions of our continent, — after excluding those spe- 
cies which range around the world in the northern hemisphere, 
or the greater part of it, or (which is nearly the same thing 
in the present view) which are unknown in Europe, — I will 
enumerate the remaining peculiar species which Japan pos- 
sesses In common with America: — 
In JAPAN. In W. N. Amerioa. In E. N. America. 
Anemone Pennsylvanica 
(Coptis asplenifolia ?) 
(Trautvetteria palmata) 
Caulophyllum __ thalic- 
troides 
Diphylleia cymosa 
Brasenia peltata 
Geranium erianthum 
Rhus Toxicodendron 
Vitis Labrusea (Thunb.) 
Thermopsis fabacea 
Prunus Virginiana ? 
Spirea betulfolia 
Photinia arbutifolia, in 
Bonin. 
Pyrus rivularis ? 
Ribes laxiflorum 
(Penthorum _ sedoides, 
China) 
Cryptotenia Canadensis 
Heracleum lanatum 
C. asplenifolia 
T. palmata 
(B. peltata) 
G. erianthum 
R. Toxicodendron, var. 
T. fabacea 
S. betulzfolia 
P. arbutifolia 
P. rivularis 
R. laxiflorum 
H. lanatum 
A. Pennsylvanica 
T. palmata 
C. thalictroides 
D. eymosa 
B. peltata 
R. Toxicodendron 
V. Labrusea 
P. Virginiana 
S. betulzfolia 
P. sedoides 
C. Canadensis 
H. lanatum 
