﻿ON THE BOTANY OF JAPAN. 437 



The principal facts which this table illustrates will be apparent upon inspection, 

 although the plan upon which it is constructed does not favor the deduction of exact 

 numerical conclusions. 



The whole number of Japanese entries is about 580 



It is interesting to notice that, notwithstanding the comparative in'oximity of Japan 

 to Western North America, fewer of its species are represented there than in far dis- 

 tant Europe. Also, — showing that this difference is not owing to the separation by 

 an ocean, — that far more Japanese plants are represented in Eastern North America 

 than in either. It is, indeed, possible that my much better knowledge of American 

 botany than of European may have somewhat exaggerated this result in favor of 

 Atlantic North America as against Europe, but it could not as against "Western North 

 America. 



If we regard the identical species only, in the several floras, the preponderance is 

 equally against Western as compared with Eastern North America, but is more in favor 

 of Europe. For the number of species in the Japanese column which likewise occur in 

 Western North America, are about 120 ; in Eastern North America, 134 ; in Europe, 157. 



Of the 580 Japanese entries, there are which have corresponding 

 European representatives, a little above 0.48 per cent ; of identical species, 0.27 

 Western N.American representatives, about 0.37 " " " " 0.20 



Eastern " " " " " 0.61 " " " " 0.23 



So geographical continuity favors the extension of identical species ; but still East- 

 ern 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 confines of Eu- 

 rope, 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 the western portions of our con- 

 tinent, — after excluding those species 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 possesses in common with America : — 



VOL. VI. NEW SERIES. 66 



