And again you fall to catch the spirit of the generic name in saying 

 that you object to having e.g. acrostichoides made a npyopteris. If 

 acrostlcholdes is congeneric vrith filix-mas they must bear the same 

 ^name. I do not say they are congeneric for I do not think they are. I 

 am sure that Presl and I'ee and other continentals had a clearer idea of 

 Gfenera than Hooker but even Hooker keeps Nephrod ' uijm and Eolyst ichum 

 separate. The species that are congeneric must follow the name of the 

 genus and I only quote Up. G&?ay when I say that I believe heartily the 

 aphorism: " A species (or genus) can have only one name and that is 

 its oldest one". If acrostlcholdes is congeneric with filix-anas they 

 must both be Dryopteris for that is the oldest name applicable to any 

 part of the combination. 



I nay have done vrrong in not separating the genera as well as the 

 group which contains trifollatiaa aiid the one that contains juglandi- 

 folluni, but I have hesitated to break av/ay from the current usage as 

 regards genera, I think^that those botanists are in the wrong who have 

 united Struthiopteris and Onoclea for no one can make me believe that 

 they evor had a coiiiiTion ancestor within the genus ( l.e, are closer to | 

 ee.oh otheT ty.et they are to other groups o'utslde the combination) 

 which is I think the test of Congeneric rQlationsi 



When I get ready to revise the ferns of North America which be- 

 tween you and me is a considerable part of my summer's mission to Kew, 

 I shall express more freely ray vievfs on generiat relat ions which I con- 

 fess are now not entirely settled. I hope within the next four or five 

 years to get together sufficient data to monograph all the ferns down 

 to the Istlmis and Include those of the Antilles^ I shall have to go 

 t'lrough the collections at London, Paris, Berlin, Copenhagen as vfell as 

 those of Caj-iibri^^ 



