Abstract
An updated checklist of the vascular plants of Annobón Island (Equatorial Guinea) is presented. Two hundred and ninety-five taxa of Angiosperms in 211 genera and 68 families and 51 species of Pteridophytes in 31 genera and 18 families are listed from Annobón. The most represented families are Leguminosae (38 taxa), Gramineae (29 taxa) and Orchidaceae (28 taxa). In addition bibliographic references have been collated and checked. Thirty-eight species are included based on records from the literature where their distribution ranges suggest they should occur on Annobón. Fifty-four introduced species that have become naturalized are listed. Twenty-four taxa are recorded for the first time, three of which were not previously known for Equatorial Guinea. Peperomia blanda is recorded as a new for West Tropical Africa. At present 23 taxa are known to be endemic to Annobón or to Annobón and the islands of São Tomé or/and Príncipe. The percentage of endemic species is 7.8. The small area of Annobón and the strict application of conservation criteria indicated that every endemic of the island should be considered as threatened under IUCN guidelines. Species conservation assessments were undertaken for 23 taxa using IUCN criteria; 19 of these represent the first assessments for these species. The catalogue includes accepted names, synonyms and voucher specimens.