Notes on the fern genus Clathropteris 
Epwarp W. BERRY 
(WITH TWO TEXT-FIGURES) 
Among the more fascinating objects of paleobotanical investi- 
gation are the abundant and varied forms which have now come 
to be rather generally recognized as constituting two distinct 
families of ferns, the Matoniaceae and the Dipteriaceae, members 
of which are such characteristic and striking objects in Mesozoic 
fern floras. This interest associated with their far distant an- 
cestry is heightened by the fact of the singular association of the 
few surviving representatives of these two families at a limited 
number of localities in the oriental tropics. 
It is not my purpose, however, to attempt an elaboration of 
this subject in the present connection, since it has already been 
discussed by others* and there is, moreover, a rather extensive 
literature dealing with the different extinct generic types that 
seem to be referable to the one or the other of these families 
All that will be attempted in the present brief contribution will 
be the placing on record of certain observations on new material 
belonging to the genus Clathropteris and a discussion of its bear- 
ing on the probable habit of these ferns. 
During a visit to the Richmond (Virginia) coal field during 
1911 I collected for the United States National Museum a re- 
markably fine specimen of the so-called Clathropteris platyphyiia, 
which, in so far as I recall, was the most complete specimen of this 
ubiquitous form that has ever been collected. This specimen 
was about 40 X 55 cm. and showed several dichotomies of the 
stipe. During its shipment to Washington the edges were broken 
and the surface abraded so that only a very inferior specimen 
remains. A counterpart of a portion of the face of this specimen 
“* Seward, A. C. On the structure and affinities of Matonia pectinata, R. Br., 
with notes on the geological history of the Matonineaer Phil. 
& 
Trans. Roy. Soc. 
Lond. B, 191: i hae — Seward, A. C., & Dale, E. On the structure and 
affinities of Dipter the geological hist of the Dipteridineae. Idem., 
B, 194 : 487-513. I90r. 
279 
