226 DAKWINIANA. 



The hypothesis supposed a gradual modification of 

 species in different directions under altering conditions, 

 at least to the extent of producing varieties, sub-spe- 

 cies, and representative species, as they may be various- 

 ly regarded ; likewise the single and local origination 

 of each type, which is now almost universally taken for 

 granted. 



The remarkable facts in regard to the Eastern 

 American and Asiatic floras which these speculations 

 were to explain have since increased in number, espe- 

 cially through the admirable collections of Dr. Maxi- 

 mowicz in Japan and adjacent countries, and the criti- 

 cal comparisons he has made and is still engaged upon. 



I am. bound to state that, in a recent general work * 

 by a distinguished European botanist, Prof. Grisebach, 

 of Gottingen, these facts have been emptied of all 

 special significance, and the relations between the 

 Japanese and the Atlantic United States flora declared 

 to be no more intimate than might be expected from 

 the situation, climate, and present opportunity of in- 

 terchange. This extraordinary conclusion is reached 

 by regarding as distinct species all the plants common 

 to both countries between which any differences have 

 been discerned, although such differences would proba- 

 bly count for little if the two inhabited the same coun- 

 try, thus transferring many of my list of identical to 

 that of representative species ; and then by simply 

 eliminating from consideration the whole array of rep- 

 resentative species, i.e., all cases in which the Jap- 

 anese and the American plant are not exactly alike. 



1 " Die Vegetation der Erde nach ihrer klimatischen Anordnung," 

 1871. 



