On the Nomenclature of the Leaves of Fossil Dicotyledons.* 



In Vol. XXV., Nos. I and 2, of the " J^otaiiisches Centralblatt," 

 A. G. Nathonst jiublishes an interesting article in which he 

 discusses the difficulties \\liich present themselves to the pal.x-on- 

 tologist in classifying and naming fossil dicotyledons on the 

 characters of their leaves only. 



The author proposes the following methods which he intends 

 to employ in his future publications, and invites his co-workers 

 in this field to adopt the same rule, viz : 



Those species of which leaves only are known, are to be 

 named after the genus with which they agree best, with the addi- 

 tion of the termination — pJiylliivi. Therefore, we ought not to 

 say Magnolia Capellini, Hecr., but MagnolipJiylhun Capellini, etc. 

 Such a name would indicate that the leaf in question seems to 

 resemble most the leaves of a Magnolia, and therefore possibly 

 belongs to that genus. If afterwards, together with this leaf, 

 flower and fruit should be found, which, without any doubt, be- 

 long to Magnolia, the leaf could then be classified with Mag- 

 nolia. In the case of leaves for which analagous forms are 

 not to be found among living plants, independent generic names 

 are to be used, as heretofore, e. g., Credneria, ProtopJiyllnm, etc. 



Another part of the article refers to the identification of fossil 

 leaves found in dififerent localities, at great distances from each 

 other. In most such cases slight differences in form, etc., are, 

 at present, not taken into consideration, and the leaves are placed 

 in the same species. Thus the leaf A is identified with the leaf 

 B (from a distant locality), afterward C with B, then D with C, 

 and finally D with A ; in reality, the name of this supposed 

 single species may possibly stand for a whole group of species. 



In order to rnect this difificulty the author proposes to employ 

 a ternary nomenclature. Suppose a leaf were found in Japan 

 which resembles Acer trilobatiim so much that it would not be 

 advisable to make a new species of it, although the similarity is 

 not perfect ; this leaf ought to be called Acer trilobatuvi Japon- 

 ic um. 



* Abstracted by Professor Jos. Schrenk . 



