38 
On the Nomenclature of the Leaves of Fossil Dicotyledons.* 
In Vol. xxv., Nos. 1 and 2, of the “ Botanisches Centralblatt,”’ 
A. G. Nathorst publishes an interesting article in which he 
discusses the difficulties which present themselves to the palazon- 
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—phyllum. Therefore, we ought not to 
say Magnolia Capellini, Heer., but Magnoliphyllum 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, Protophyllum, etc. 
Another part of the article refers to the identification of fossil 
leaves found in different 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 meet this difficulty the author proposes to employ 
a ternary nomenclature. Suppose a leaf were found in Japan 
which resembles Acer trilobatum 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 trilobatum Japon- 
icum. 
* Abstracted by Professor Jos. Schrenk, 
