Oct. 1915.] b. HAYATA—CAX PROSAPTIA PROPERLY BE PLA< EI> ETC. 167 



forms between this Davallia-Yike sorus and the normal Crvpto- 

 sorus-sorus are to be found in the development of the fructifi- 

 cation in Prosaptia, and also are to be seen in the full-grown 

 sorus of Polypodium urceolare, as have stated above. Conse- 

 quently, Prosaptia is in its vegetative as well as its propa.ua- 

 tive organs so closely related to Polypodium phylogeneticallv, 

 that it is quite proper to unite them into one genus. 



Now let us consider whether the resemblance between Pro- 

 saptia and Dayallia which seems apparently very close is really 

 an indication of phylogenetic kinship or a mere accidental 

 feature. To decide this question fundamentally, I made the 

 same stud}' on Dayallia, as I had done before on Cryptosorus 

 and Prosaptia. ' Dayallia is a fern not of indefinite but of defi- 

 nite growth, and all the sori on one frond mature simultane- 

 ously. I took a young shoot of D. bullata nearly 5 crrf. long, 

 just coming out from the rhizome, partly coiling and partly 

 unfolded, yet bearing beautiful sori of a very young stage. I 

 examined the frond under a binocular microscope with cl 2 ob- 

 ject-glasses and found the sori in a stage just before sporan- 

 gium-formation. Indusium-formation was just beginning a 

 little below the apex of the lobes. The indusium was coming 

 out like a broad quadrangular scale, attached at its base to 

 the surface of the frond, but leaving its margin quite free from 

 the latter. There was no depression whatever. The type of 

 this kind of indusium is represented in a full grown sorus ot 

 Humata. It is totally different from the type seen in Prosaptia. 

 It is, therefore, highly probable that Dayallia is derived directly 

 from Humata ; and Prosaptia from Polypodium. Consequently, 

 it is clear that the resemblance between Dayallia and Prosaptia 

 is merely an accidental feature. The two can never be united 

 into one, nor should the one be treated as a subgenus of the 

 other. One might as well take a pseudomorph for a true crys- 

 tal, as to take Prosaptia for a Dayallia. 



After considering all the above mentioned cases, I have been 

 led to conclude that Prosaptia in the first place, should be 

 taken into Polypodium and for convenience sake retained as a 

 subgenus of the latter, as is the case with Cryptosorus ; and 



