26 AMERICAN FERN JOURNAL 
means of distinguishing species. And the resultant 
breaking-up of too widely spread and heterogeneous 
groups is adding much to our knowledge of the real 
laws of plant distribution. 
The latest American fern to be separated from the 
European species with which it had long been associ- 
ated, is the local Polystichum of California, hitherto 
referred to P. aculeatum. This, Mr. Maxon finds after 
a study of abundant material, differs constantly from 
the European plant in its “invariably oblique, less 
strongly auricled and more copiously filiform-paleaceous 
pinnules and by its fimbriate-ciliate indusia.’”’ It must, 
he concludes, be considered a separate species and 
he names it Polystichum Dudleyi, in honor of the late 
Prof. W. R. Dudley.‘ 
Prof. E. W. Berry has discussed a fossil fern, Clathrop- 
teris platyphylla, which, if his tentative restoration of it 
is correct, possessed a most peculiar habit. The main 
rachis, as pictured by him, divides into two branches 
which diverge at a wide angle. Each branch bears 
near the base from ten to thirty lanceolate pinnae, 
all on one side, in a fashion irresistably suggesting the 
feathers on the leg of a chicken. Above these pinnae 
the branches are naked for a space and then carry 
out the chicken analogy by producing at the end a 
palmately arranged cluster of pinnae which does very 
well for the foot. 
Prof. Berry discusses interestingly the relationships 
of the genus Clathropteris. In the form of its pinnae - 
and its, for the most part, regularly reticulate venation 
it is very like the present genus Drynaria, though it 
seems actually not to be related to it, but to represent 
the ancestral type of Dipteris.® 
‘Maxon, W. R. A new oo from California. Journ. Wash- 
ington Acad. Sci. 8: 620-622. Nov. 918. 
‘ Berry, E. W. Notes on the fern ss sige pda Bull. Torrey 
Bot. iia 45: 279-285, figs. 1 and 2. July, 
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