The Ferns and Fern-Allies (Pteridophyta) of the Cape Verde Islands, West Africa

The present publication revises the 34 known species of ferns and fern-allies from the Cape Verde Islands. The work is based on herbarium material and material gathered by the senior author during nine excursions and comprises 29 taxa.

It was not possible to confirm the presence of two species (Asplenium (Ceterach) sp. and A. marinum), thus the actual number of species of pteridophytes on the archipelago is 32; it seems very unlikely that the two above mentioned species ever occurred.

The present work is the first comprehensive account for 80 years. The phytogeographical analysis shows a large proportion of species to have a worldwide or palaeotropic distibution. Only six taxa (Asplenium aethiopium ssp. braithwaitii, Asplenium hemionitis, Davallia canariensis, Diplazium caudatum, Dryopteris oligodonta, Notholaena marantae ssp. subcordata) demonstrate a relationship to the neighbouring Canary Islands.

Special emphasis has been given to the status of the species. One species (Dryopteris pentheri) is extinct and another (Ophioglossum reticulatum) has been classified with a prolonged absence, thus this species has not been recorded for many years. Five species (Asplenium hemionitis, Diplazium caudatum, Dryopteris oligodonta, Osmunda regalis, Psilotum nudum) are critically endangered, one is endangered (Ophioglossum lancifolium), five (Adiantum philippense, Cosentinia vellea ssp. vellea, Davallia canariensis, Notholaena marantae ssp. subcordata, Ophioglossum polyphyllum) are probably endangered and 8 taxa (Actiniopteris radiata, Adiantum reniforme ssp. reniforme, Asplenium adiantum-nigrum ssp. adiantum-nigrum, A. trichomanes ssp. quadrivalens, Cystopteris fragilis, Lycopodiella cernua, Marsilea coromandeliana, Pellaea viridis) are classified as rare. Thus 21 species (65.6%) of the Capeverdean fern flora are classified as extinct or threatened.

The remaining 11 species (Adiantum capillus-veneris, Asplenium aethiopicum ssp. braithwaitii, Cheilanthes acrostica, Christella dentata, Equisetum ramosissimum, Hypodematium crenatum, Nephrolepis undulata, Pteridium aquilinum, Pteris vittata) are not threatened at present.

The information about the threat of the species is compiled in the second revised Red List from the Cape Verde Islands.

Each species is described and illustrated and a list of all material seen is given. For threatened species distribution maps are given.