20-1 FERNS : BRITISH AND FOREIGN. 



4. H. Tyermanii, Moore ; Gard. Ghron. 1871, p. 870, 1. 178. 

 Davallia Tyermanii, Buher, in Appendix to Hook. 

 Syn. Fil. p. 467.— India (non Trop. West Africa as 

 stated in Gard. Cliron.). 



3. DAVALLIA (p. 75). 



10a. D. Mauritiana, Eooh. Sp. Fil. 1, t. 55, B. — Mauri- 

 tius. K. 



12a. D. pallida, Mett. ; Bah. in Hook. Syn. Fil. p. 469. D. 

 Mooreaua, Masters; Gard. Glicor. 1869, p. 964. — 

 Island of Aneitum. K. 



4. LETTCOSTEGIA (p. 77). 



6a. L. membranulosa, /. Sm. Davallia mernbrannloss, 

 Wall; Boole. Sp. Fil. 1, t. 53, A.— India. 



Obs. — This genus was founded by Presl in 1836, on the 

 Davallia immersa of Wallicb, to which additional species have 

 been added, all having articulate vernation, and closely related 

 to true Davallia. Presl also founded another geDus on the 

 Aspidium nodosum of Blume, which he termed Acroplwrus ; 

 its vernation is fasciculate and adherent, producing large de- 

 compound fronds 2-4 feet in height, having the sori seated on 

 the apex of the laceneae, with a lateral attached indnsinm, 

 not technically differing in form from many species of Lastrea. 

 While admitting it as a distinct genus, I consider it to bo 

 naturally allied to Lastrea ; nevertheless, in Moore's " Index 

 Pilicum " the whole of the species of Leucostegia are placed 

 under Acroplwrus ; thus forming an unnatural association, as if 

 Davallia canariense was placed in affinity with Lastrea, dilatata 

 and its allies. Acroplwrus nodosa is a native of India, and has 

 not yet been introduced in a living state. 



