327 



genus to the later. His opinion is, in other words, that the fern so well 

 defined from others should be retained as a distinct genus, however close 

 affinity it may have to Polypodium. 



Let me here state briefly just a few lines as to what constitutes Prosaptia. 

 It is a fern closely resembling Polypodium obliquatum in many respects es- 

 pecially in its vegetative organs, but having a fructification nearly similar to 

 that of Davallia. Modern pteridologists, such as HOOKER^, BAKER**, CHRIST**, 

 CHRiSTENSEN 4) and DIELS S) , maintain that while Prosaptia is separable from 

 Polypodium, it is quite assignable to Davallia, and they rank down the 

 former to a subgenus of the latter. 



My opinion regarding Prosaptia is quite different from the general view 

 of the leading authors, and is rather inclined to the statement of SMITH, who 

 regards it as referable to Polypodium. For convenience sake, I shall here state 

 my conclusion, before I go into details as to my reasons therefor. My opinion 

 is that Prosaptia bears too close affinity to Polypodium to permit its separation 

 from the latter genus, and that it differs from Davallia so widely that to 

 assign it to the latter would at once entirely violate what we call the natural 

 system. In other words, Prosaptia is really a Polypodium and only imitates 

 Davallia. It is a fern nearly the same as Polypodium in its phylogeny ; 

 but it is absolutely different from Davallia in its derivation. 



The present question as to the natural position of Prosaptia has arisen in 

 my mind, since my discovery in Formosa of the present new fern, Polypodium 

 urceolare HAYATA (Fig 136 and 137, a-f ), which veiy closely resembles Prosaptia 

 contigua in every respect, but has a fructification tending more toward Poly- 

 podium obliquatum than toward the Prosaptia. This led me to examine the 

 new plant more closely in its vegetative and propagative organs. The sori are 

 under the margin of the frond, have orifices which open obliquely on the under 

 surface, and are margined with elevated ridges beset with bristles. Thus they 

 are of a form just intermediate between Prosaptia contigua and Polypodium 

 obliquatum. The gap in respect of generic characters of the two genera as 

 retained by COPELAND, is practically filled by the presence of this new fern. 



1) HOOKER, W. J. Species Filicum I. p. 160. 4) CHRISTENSEN, C. Index Filicum, p. 589. 



2) BAKER, J. G. Synopsis Filicura p. 94. 5) DIEIJS, L. I.e. p. 212. 



3) CHRIST, D. Farnkriiuter der Erde, p. 305. 



