128 ESS A YS. 



western, and forty-one eastern North America. And fifteen 

 are western and not eastern ; twenty-one eastern and not 

 western ; and twenty common to both sides of the continent. 

 Eight or ten of these fifty-six species extend eastward into 

 the interior of Asia. 



On the other hand, the only species which I can mention 

 as truly indigenous both to Japan and to Europe, but not 

 recorded as ranging through Asia, are : — 



Euonymus latifolius, Valeriana dioica, Pyrola media, 

 Fagus sylvatica, Streptopus amplexifolius, Blechnum spi- 

 cant, Athyrium fontanum. 



Two of these species extend across the northern part of the 

 American continent and on to the Asiatic ; another occurs on 

 the northwest coast of America ; and another, the Fagus, is 

 represented in eastern America by a too closely related spe- 

 cies. It is noteworthy that not one of these seven plants is 

 of a peculiarly European genus, or even a Europaeo-Siberian 

 genus ; while of the fifty-six species of the Americo-Japanese 

 region wanting in Europe, twenty are of the extra-European 

 genera, seventeen are of genera restricted to the North 

 American, east Asian, and Himalayan regions (except that 

 Brasenia has wandered to Australia) ; fourteen of the genera 

 (most of them monotypic) are peculiar to America and Japan 

 or the districts immediately adjacent ; one is peculiar to our 

 northwest coast and Japan ; and eight are monotypic genera 

 wholly peculiar (Brasenia excepted) to the Atlantic United 

 States and Japan. Add to these the similar cases of other 

 American species (nearly all of them particularly Atlantic- 

 American) which have been detected in the Himalayas or in 

 northern Asia, — such as Menispermum Canadense (Daw- 

 ricum, DC), Amphicarpaia monoica? Clitoria Mariana, 

 Osmorrhiza brevistylis, Monotropa unijlora, Phryma lepto- 

 stachya, Tipularia discolor ? etc., — and it will be almost im- 

 possible to avoid the conclusion that there has been a peculiar 

 intermingling of the eastern American and eastern Asian 

 floras, which demands explanation. 



The case might be made yet stronger by reckoning some 

 subgeneric types as equivalent to generic in the present view. 



