326 rOLYPODIACE^E. 



ad marginem, baud ad apicem siti, sub segmento singulo 1-8 valde iininersi ; 

 cavis sororum ascendentibus 1 mm. longis, ore elevato mm. in diametro, circum 

 oria hispidis. 



HAB. Mt. Arisan, prope Senninbora, leg. TAKEO ITO, Aprili. 1914. 



This new fern and Polypodium Kanashiroi HAYATA are species belonging 

 to Prosaptia which is, according to the leading pteridologists, regarded to be a 

 subgenus of Davallia. Yet, quite contrary to the current opinion, I have here 

 taken the ferns as species of Polypodium. This requires a full explanation. 



Prosaptia is a genus which was established by PRESL/ ) as early as 1836, 

 on the species Prosaptia contigua, which was then found in the Philippines. 

 It is, as has been remarked by several authors, a fern closely resembling Poly- 

 podium obliquatum in its external features, especially in its rhizomes, scales, 

 hairy stipes and fronds, with much the same kind of division and venation. 

 But it has been regarded by several leading pteridologists as widely different 

 from Polypodium in its fructification. It is, therefore, often referred to as 

 representing a class of ferns which, though closely alike externally, should be 

 treated as quite different systematically. 50 The genus under consideration is 

 assigned to the vittariere by the founder, as it has a sorus located at the 

 margin of the frond as is the case with Vittaria. Fee 3) in his classical " Ex- 

 position des Fougeres " expresses his opinion about the natural position of the 

 genus and says that it might be better placed in the Davalliese, as it has 

 a sorus somewhat resembling that of Davallia. Later on, SiniTH 4) reduces the 

 genus to Polypodium, on the ground that it bears so close a relation to the 

 latter genus that it should be regarded as inseparable. COPELAND S) retains 

 Prosaptia in the sense that the generic definition is to some extent admis- 

 sible, so far as it is convenient for systematizers, and he finally concludes that 

 Prosaptia is a good genus quite clearly defined from Polypodium, although he 

 admits that SMITH does not violate the natural system in reducing the former 



1) PRESL, C. B. Tentamen Pteridographie, (1836) p. 165. 



2) DIETS, L. Pteridophyta, in ENGLER u. PRANTL, Nat. Pfl.-fara. 1-4, p. 144. 



3) FEE, A. L. A. Genera Filicum, Exposition des Genus de la Famille des Polypodiac^es, 

 p. 324. 



4) SMITH, J. in HOOKER'S Journ. Bot. IV. (1842) p. 46, I regret to say that I could not 

 read SMITH'S paper, as it is not accessible to me. 



5) COPELASTD, E. B. in Philip. Journ. Scien. Suppl. I. (1906) p. 157. 



