APPENDIX. 173 



duce adaptive " changes in organization " ; wherefore, as the Presi- 

 dent of the Linnsean Society has aptly remarked, 1 " We have a right 

 to ask of him, What is the previous organization upon which he 

 imagines climate to have worked to produce allied species in one 

 region and representative species in distant regions ? " The differ- 

 ence here between Grisebach's conception and our own is, that we 

 consider climate and other external conditions to have acted upon 

 common ancestors in each case ; but he apparently declines to con- 

 jecture what they acted upon. 



In conclusion I may advert to one instance, in which it would ap- 

 pear, either that widely different climates have originated the same 

 or closely similar species, or else that one and the same species (one 

 of those common to the United States and Japan) has been dis- 

 persed over the globe in a manner and to an extent that place it be- 

 yond the reach of explanations limited to the results of forces still 

 in activity and means of dispersion still available. Brasenia peltata 

 inhabits : 1. The Atlantic United States, from Canada to Texas ; 2. 

 Oregon, or rather Washington Territory, a single known station at 

 Gray's Harbor, on the Pacific, latitude 47° ; and Clear Lake, in 

 California, latitude 39° ; 3. Japan ; 4. Khasya and Bhotan, altitude 

 4-6000 feet ; 5. Australia, Moreton Bay, etc. ; 6. West Africa, in 

 a lake in Angola ! 



1 Address of George Bentham, Esq , President of the Linnaean Society, 

 etc., read May 24, 1872. 



