2 Bower.—Studies in the Phytogeny of the Filicales . VII. 
based upon the relatively early assumption in descent of the superficial 
position in the former, and the retention of the marginal position in the 
latter relatively late, or even to the present day. The Superficiales will then 
group themselves in relation to the relatively primitive Gleicheniaceae, while 
the Marginales may be affiliated to the Schizaeaceae ; and we may anticipate 
that certain types will take an intermediate position. The underlying 
hypothesis would be, that in the ancestry of the Leptosporangiate Ferns the 
marginal position of the sporangia was prevalent, or perhaps universal. 
The Ferns grouped under the comprehensive heading of the 4 Pterideae ’ 
by Diels 1 present special difficulties in their phyletic treatment from such 
a point of view as this, because they illustrate more clearly than any other 
group the gradual departure from the marginal position in the course of 
descent. I had long recognized this, 2 and have accordingly delayed the 
detailed study of them till the other main sequences should have been 
sketched out. This having now been done, the attempt may be made to 
group these ‘ Pterideae ’ phyletically. The best way to approach this will 
be to start from those types which may be held as relatively primitive. 
That is the method which has regularly been pursued in these studies. 
Their relation is ultimately to the Schizaeaceae. This was already suggested 
by Sir W. Hooker, who remarked 3 that Mohria combines the capsules of 
the sub-order Schizaeaceae with the habit of Cheilanthes. On the other 
hand, Prantl showed 4 that the Schizaeaceae are the typical family of 
primitive Ferns with a marginal origin of their sporangia. Accordingly 
certain facts relating to the Schizaeaceae which will help our comparisons 
will first be given. This will form a necessary introduction to the phyletic 
study of the Pterideae. 
Schizaeaceae. 
In his monograph on the Schizaeaceae (Leipzig, 1881) Prantl laid 
a secure foundation for the detailed knowledge of the living representatives 
of this family, in point of external form, dermal appendages, anatomy, and 
the position and development of the sporangia. If all these characters be 
taken into account, together with such additional facts as have been acquired 
later, the general conclusion follows that Lygodium is the most primitive of 
the living genera ; that Schizaea occupies a position in certain respects more 
advanced ; and that Anemia and Mohria are relatively advanced genera. 
The chief facts have already been summarized elsewhere. 5 Here certain 
facts relating to anatomical structure and to the sporangia may be added, 
which may help the comparisons to be made later. 
1 Nattirl. Pflanzenfam., i. 4, p. 254. 
2 Compare also Prantl, Die Farngattungen Cryptogramme u. Pellaea. Engler’s Jahrb., iii, 
p. 403. 
3 Syn. Fil., p. 436. 
5 Land Flora, pp. 549-51. 
4 Schizaeaceae, pp. 39-46. 
