Prof. Asa Gray on Sequoia and its History. 6 1 



many as far south as Chili. The same may be said of the 

 plants of the intervening great plains, except that northward 

 and in the subsaline vegetation there are some close alliances 

 witli the flora of the steppes of Siberia. And along the crests 

 of high mountain-ranges the arctic alpine flora has sent south- 

 ward more or less numerous representatives through the whole 

 length of the countr}^. 



If we now compare, as to their flora generally, the Atlantic 

 United States with Japan, Mandchuria, and Northern China, 

 i. e. eastern North America \v\t\\ eastern North Asia (half the 

 earth's circumference apart), we find an astonishing similarity. 

 The larger part of the genera of our own region Avhich I have 

 enumerated as wanting in California are present in Japan or 

 Mandchuria, along with many other peculiar plants, divided 

 between the two. There are plants enough of the one region 

 which have no representatives in the other. There are types 

 which appear to have reached the Atlantic States from the 

 south ; and there is a larger infusion of subtropical Asiatic types 

 into temperate China and Japan : among these there is no re- 

 lationship between the two countries to speak of. There are 

 also, as I have already said, no small number of genera and 

 some species which, being common all round or partially round 

 the northern temperate zone, have no special significance 

 because of their occurrence in these two antipodal floras, al- 

 though they have testimony to bear upon the general question 

 of geographical disti'ibution. The point to be remarked is that 

 many or even most of the genera and species which are peculiar 

 to North America as compared with Europe, and largely pecu- 

 liar to Atlantic North America as compared with the Califor- 

 nian region, are also represented in Japan and Mandchuria, 

 either by identical or by closely similar forms ! The same 

 rule holds on a more northward line, although not so strikingly. 

 If we compare the plants, say of New England and Pennsyl- 

 vania (lat. 45° -47°) , with those of Oregon, and then with those 

 of North-eastern Asia, we shall find many of our owm curiously 

 repeated in the latter, while only a small number of them can 

 be traced along the route even so far as the western slope of the 

 Rocky Mountains. And these repetitions of Eastern American 

 types in Japan and neighbouring districts are in all degrees of 

 likeness. Sometimes the one is undistinguishable from the 

 other ; sometimes there is a difference of aspect, but hardly of a 

 tangible character ; sometimes the two would be termed marked 

 varieties if they grew naturally in the same forest or in the 

 same region ; sometimes they are what the botanist calls re- 

 presentative species, the one answering closely to the other, 

 but with some diflerences regarded as specific ; sometimes the 



