CHKISTEXSEN— FEENS OF SEYCHELLES AND ALDABRA 409 



II. 28 (10 + 6+12) are confiued to Africa, including the islands; 18 of these are 

 not found in tropical Africa, but are endemic in the South-eastern islands, and 12 

 species are endemic in the Seychelles. Nearly all these endemic species may 

 be regarded as specialized forms of groups which are richly developed in other 

 regions, perhaps with the exception of Ptens Barklyce, a peculiar species, which is 

 probably most closely related to the Mascarene Ochropteris. If we take the 

 relationship of the endemic species into consideration, we find that some of them 

 point westwards {Dryopteris Wardii, Folypodlum Pervillei, Elaphoglossum 

 Hornei), others eastwards {LeptoGliilus bipiimatiJidHS, Lindsaya Kirkii, L. Hornei), 

 while Asplenium complanatum, Stejiochlcena Pervillei, and perhaps Polypodium 

 albobnmneum are members of groups specially developed in the Mascarene and 

 other South-eastern African islands. 



III. 28 (18 + 10) species have their maximum in tropical Asia and Polynesia ; 10 

 of these reach their western limit in the South-eastern African islands, and among 

 these there are 4 species {Asplenium tenerum, A. hulbiferum, Antropliyum ccdlifolium, 

 and Schizcea digitata) which have their western boundary in the Seychelles. 



The above may be summarized thus : the fern-fiora of the Seychelles is a mixture of 

 western and eastern species, the latter being in majority. Five species here reach their 

 eastern limit, four their western. The fern-flora as aAvhole shows no peculiar character ; 

 16 per cent, of the species are endemic. 



From the Aldabra group only one species is known, the common mangrove fern, 

 Acrostichum aweiim. 



HYMENOPHYLLACEiE. 



1. Trichomanbs erosum, Wilid. (?) ; Baker, Fl. Maur. 464 ; C. Chr. lud. 639. — 



? T. CKSpidatnm, Kuhn, Bot. v. Ost-Afr. 68. 



Common in the mountain forests. Home. Silhouette, 2000 feet on trees, Gardiner ! 



It is with the greatest doubt that I refer the specimens from the Seychelles to T. erosum, 

 Willd., which is a West-African species. In general habit the small leaves agree muoli 

 more witli T. citspidahm,y^^\\\i\., but they differ in the lack of an intramarginal, spurious 

 vein and in the more distinct midril) and lateral veins. The fronds vary in sliape, 

 from circular and entire to triangular-oblong, 3 cm. long by 1-1^ cm. broad, and 

 irregularly repand or serrate, not regularly pinnatifid as in the true T. erosum. The 

 form may be specifically distinct from T. erosum as well as from T. cmpidattim. 



2. TmcHOMANES CUPRESSOIDES, Desv. Prodr. 330, 1827 ; C. Chr. Ind. 638.-2". ohscurmn, 



var. ptectinata, Mett. ; Kuhn, Fil. x\.fr. 35. T. rigidnm, Baker, Fl. Maur. 465. 

 Mahe, Silhouette, and Long Island, Gardiner ! A typical fern on rocks onmountaius, 

 2000-2500 feet. 



.52—2 



