164 THE BOTANICAL MAGAZINE. [Vol. xxix. No. mb. 



walls. The scales are also remarkable, being composed of 

 polygonal cells with rather thick brownish walls arranged in 

 one layer, and beset with bristles on the other surface. Pro- 

 saptia also closely resembles Polypodium decrescens. The scales 

 of the latter differ from those of the former only in lacking 

 bristles. These anatomical affinities all point to their being 

 congeneric ; for such a general agreement in character is one of 

 the most important points in the classification of genera, as 

 is shown by C. Christensen, and others. The anatomical 

 characters seen in the structure of hairs and scales are mostly 

 hereditary 1 ' rather than posterior, and of all characters are 

 least subject to change in the course of the phylogenetical develop- 

 ment of species. They are, therefore, the most reliable char- 

 acters for the determination of the kinship of genera. 



Let me now briefly state how far Prosaptia agrees with 

 Davallia in respect of its vegetative organ. The rhizomes of 

 the latter are long-creeping with remotely arranged fronds, 

 while those of the former are short-creeping with densely ar- 

 ranged fronds. The scales of Davallia are composed of cells 

 with very thin reddish walls arranged in one laj'er with no 

 trace of bristles, and are totally different from what we have 

 observed in Prosaptia or Polypodium ohliquatum. The hairy 

 stipes so peculiar to the latter two have never been found in 

 Davallia. Therefore, so far as the vegetative organs are con- 

 cerned, Prosaptia is not congeneric with Davallia. 



Now let me consider more precisely a comparison of the 

 same ferns in respect of fructification. My opinion is that the 

 fructification of Prosaptia is altogether the same as that of 

 Polypodium in its beginning, but totally different from that of 

 Davallia in its beginning, as I shall show later on. Before I 

 go into details, I must pause to consider what the fructification 

 of Polypodium ohliquatum or of its allied species is like. In 

 the full grown form, the sori of this fern look very different 

 from the ordinary sori of a normal Polypodium, and for this 



1) Christensen, C. — On a natural classification of thes pecies of Dryopteris p. 

 75 ; Soleredee — Systeroatische Anatomie der Dikotyledonen p. 937. 



