334 | The Philippine Journal of Science 1917 
are more perfectly preserved today by Matonia and Dipteris. 
His last paper goes into this subject more thoroughly and more 
conclusively. In field work, during all my years in this part. 
of the world, I have been constantly struck by the common oc- 
currence of dichotomy as a sort of monstrosity of the fronds 
of Polypodium, using the name now in the broad sense in which 
it is used, for example, in the Natiirliche Pflanzenfamilien. 
While occasional forked fronds are found in the ferns of almost 
every group, they are rare in most groups, and relatively very 
common in this one. If I were to go over the very large collec- 
tions in Manila, mounted and unmounted, I do not believe that I 
would find dichotomous fronds of less than 75 species which at 
present bear the generic name Polypodiwm. In some of these it 
is common enough to be characteristic, as in P. ceratophyllum 
Copel. of Borneo, and P. Curranii Copel. of Luzon. Now that the 
probability has been established, on wholy different grounds, 
that these ferns are descendants from a group characterized by 
dichotomy, the occurrence of such fronds in many different © 
species should be regarded as valid contributary evidence. 
In search of further points of connection and possible prim- 
itive groups, I have examined a number of ferns with regard 
to the characters emphasized by Bower. Polypodium incurva- 
tum Blume is strikingly suggestive of Christiopteris in form of 
sterile fronds and is somewhat dimorphous. Its annulus has 
14 or 15 cells. The spores are bilateral and tuberculate. It 
has a distinct hypodermis, but this is by no means as sharply 
and conspicuously developed as is true of most species of the 
Phymatodes group. In Christiopteris it is still less developed, 
although the layer immediately under the upper epidermis is 
somewhat different from the deeper-lying cells of the mesophyll. 
The paleae of Polypodium incurvatum are stout and peltate, not 
much drawn out to a point, with apparently entire margin (my 
material is old), almost all walls thin and not colored, except 
near the base, where the paleae are several cells thick. The 
points of resemblance to Christiopteris are not very significant. 
Polypodium Curranii Copel. is a member of the group of P. 
myriocarpum Mett., distinguished by Fée under the generic name 
Microsorium. The paleae are acuminate with the marginal 
cells alone thin; they are entire. or with obscure teeth formed 
by projections of the walls between cells. 
Drymoglossum carnosum J. Sm. has reniform spores and an 
annulus of 14 cells. The elongate sorus is supplied by a single 
bundle which is nearer the nether surface of the leaf than are ~ 
the other bundles of the same frond. The paleae are peltate 
