XLVIIl] 



ACROPHORUS— MONACHOSORUM 



253 



ACROPHORUS Presl 



Though this monotypic genus has ah-eady been discussed, and its place 

 among the Dryopteroid Ferns recognised in Chapter XLI, p. 130, it is well 

 to reconsider it here, as the question of its affinity has some similarity to 

 that of Cystopteris, with which genus its close relation was recognised by 

 Presl. Its single species A. stipellahts (Wall.) Moore had, however, been 

 previously included by Blume in Aspidinni. Hooker merged it in Davallia, 

 as D. {Leucostegia nodosa) Hk. {Syn. Fil. p. 92). Against this Von Goebel has 

 lately objected decisively {Btdt. Ann. 1926, p. 99). Diels upheld the genus, 

 placing it next to Cystopteris {I.e. p. 164), while Christ gives it near relation 

 to Struthiopteris {I.e. p. 285). The question of affinity is here like that of 

 Cystopteris, and its comparison helps to consolidate the conclusion as to the 



Fig. 749. rt: = sorus of Acrophoriis stipellatus in surface view. ( x 35.) b = z. pinnule 

 of the same showing the veins continued beyond the sori. ( x 10.) 



latter. Here the adult sorus is superficial, seated sometimes on an enlarged 

 end of a vein (Fig. 749, a), but frequently its position is lateral {b): and the 

 difference may be illustrated by the sori borne on a single leaf. The indusium 

 is basal, as in Dryopteris or Cystopteris; but it is often minute or even 

 vestigial. The stem and leaf-stalks are covered by chaffy Dryopteroid scales, 

 as they are also in Cystopteris, and the vascular system of the upright stock 

 is a dictyostele, but here with a highly divided leaf-trace. These features 

 support the alliance of Aerophorus with Cystopteris, and they confirm for 

 both the position assigned by Prantl in his Aspidiinae; that is, with the 

 Dryopteroid Ferns. 



