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Systematics and Biodiversity 5 (2): 159–186 Issued 25 May 2007 doi:10.1017/S1477200006002143 Printed in the United Kingdom C The Natural History Museum A checklist of the Rubiaceae (coffee family) of Bioko and Annobon (Equatorial Guinea, Gulf of Guinea) A.P. Davis1∗ &E. Figueiredo2 1Royal Botanic Gardens, Kew, Richmond, Surrey TW9 3AB, UK 2Instituto de Investigac¸˜ao Cient´ıfica Tropical, Trav. Cde da Ribeira 7, 1300-142 Lisboa, Portugal Email: estrelafi[email protected] submitted September 2004 accepted June 2006 Contents Abstract 159 Introduction 159 Material and methods 160 Diversity and conservation 160 A checklist of Rubiaceae for Bioko and Annobon 161 Excluded names and species records 180 Acknowledgements 180 References 181 Systematic index 184 Abstract A detailed checklist of the Rubiaceae (coffee family) occurring naturally on the islands of Bioko and Annobon (Equatorial Guinea, Gulf of Guinea) is presented, based on herbarium collections deposited in the herbaria of the Royal Botanic Gardens, Kew and The Natural History Museum, London. The checklist comprises 58 genera and 147 species, including six new generic records and 26 new infrageneric records. The total number of native Rubiaceae species occurring in Bioko is 139; three entities do not have formal names and probably represent new taxa. In Annobon there are 12 native genera and 13 indigenous species of Rubiaceae. The conservation status of two endemic species is assessed using IUCN criteria and it is proposed that they are considered Vulnerable. Key words Rubiaceae (coffee family), Bioko, Annobon, Equatorial Guinea, Gulf of Guinea, biodiversity Introduction other three islands as ‘maritime’ noting that Annobon, being the furthest from the continent, had some characteristics of The objective of the contribution presented here is to provide oceanic islands. a contemporary checklist for the Rubiaceae (coffee family) of Bioko has a lower percentage of endemic flowering plants Bioko and Annobon, with annotated taxonomic entries, and compared with Sao˜ Tome,´ Pr´ıncipe and Annobon (i.e. the other notes on diversity and conservation. islands in the Gulf of Guinea) but has a higher level of species The islands of Bioko (‘Fernando Po’) and Annobon are diversity. Bioko is of particular importance in the context of the two of the four Gulf of Guinea Islands, and are part of Equat- African flora because it is the type locality for many African orial Guinea. The other two islands (Sao˜ TomeandPr´ ´ıncipe) taxa. For example, and not taking into account infraspecific form a separate country. Biogeographically these islands are taxa, for 41 of the 139 species of Rubiaceae present in the part of the the Lower Guinea centre of endemism, within the island, the type specimen was collected on Bioko. The reason Guineo-Congolian Domain (White, 1979). for this bias is historical, as the first comprehensive studies of Bioko is the larger of the four islands and the closest to the the flora of Africa were undertaken in England based on col- African mainland (32 km), lying on the continental shelf. It was lections deposited at the Royal Botanic Gardens, Kew (K). The characterized by Exell (1973) as a ‘littoral’ island, and shown collections made in Bioko by Mann (in 1859–1862), Barter (in to be floristically similar to the continent. Exell described the 1858) and Vogel(in 1840–1841) were among the first available ∗ Corresponding author. Email: [email protected] for tropical Africa. 159 160 A.P. Davis & E. Figueiredo The Flora of West Tropical Africa (Hutchinson & Dalziel, species but instead to summarize data that are available from 1931, 1963) treated the flora of Bioko but not of Annobon. field collections. The general distribution for each accepted The flora of Annobon was treated by Exell (1944), and later taxon is given under the heading ‘Distribution’, and was ob- the flora of both islands was included in a checklist by Exell tained from a draft version of the World Rubiaceae Checklist (1973). There is a more recent list for Equatorial Guinea (Aedo (http://www.kew.org/data/rubiaceae/ Rubiaceae.htm). The dis- et al., 1999), but it does not convey realistic information on tribution data for the World Rubiaceae Checklist was obtained plant diversity, being a list of all names and not distinguishing from literature and herbarium study (Govaerts et al.,inprep). between accepted names and synonyms. For the Rubiaceae The distribution of each species is given in brief narrative text (coffee family) of Bioko 153 taxa (excluding cultivated Coffea) and in code, following the TDWG system (Brummit, 2001) to are listed, but the real figure for the diversity of the family level-3, although the codes for the Gulf of Guinea Islands have known at the time was 118 taxa, for example. been added here to level-4. The history of botanical collecting in Bioko and Annobon The starting point for this checklist is the work by Exell has been recently treated in the literature (Aedo et al., 2001). (1973), which represents the most recent angiosperm checklist After identifying the numerous collections made in Bioko in available for the Gulf of Guinea islands. To avoid repetition the 1980s by M.F. Carvalho and J.F. Casas, it became clear we have not included synonyms or literature references already that previous enumerations of Rubiaceae occurring on Bioko cited in Exell’s work. Taxa recognized as accepted by Exell and Annobon were very much out of date and that a new but later placed into synonymy have been cited here. We have, enumeration was urgently required. The Rubiaceae of Sao˜ however, included all the names of Rubiaceae for Bioko and TomeandPr´ ´ıncipe having been recently revised (Figueiredo, Annobon enumerated in the more recent list for Equatorial 2005), it was decided that the revision should be extended to Guinea by Aedo et al. (1999). This is necessary because the the remaining islands. checklist of Aedo et al. does not distinguish between synonyms and accepted names (see above). The citations of basionyms and synonyms, where applicable, are given in italics under Material and methods the relevant accepted name. Full synonymy for each accepted name can be found in the World Rubiaceae Checklist (see The work presented here is based on herbarium collections above). made in Bioko and Annobon and deposited at the Royal After each genus entry references for useful taxonomic Botanic Gardens, Kew (K) and The Natural History Museum literature (e.g. keys, descriptions, distribution) have been ad- London (BM). Duplicates from other herbaria are cited if ded under the heading ‘Useful taxonomic treatment’. General known, but were not seen by us. Herbarium abbreviations works have mostly not been added under this heading; use- follow Holmgren et al. (1990). ful, general floristic treatments include Flora of West Tropical Most of the data used herein is based on the collections Africa (Hutchinson & Dalziel, 1963), and Flore du Gabon made by Carvalho and F. Casas. Nearly all of their collec- (Halle,´ 1966, 1970). A checklist by Figueiredo (2005) should tions deposited at K lack collecting localities and dates. We be consulted for the the Gulf of Guinea islands of Sao˜ Tome´ succeeded in obtaining these data for some Carvalho speci- and Pr´ıncipe. For widespread taxa and generic keys, the fol- mens, from Francisco Cabezas at the Real Jard´ın Botanico´ lowing works are useful: Flora Zambesiaca (Verdcourt, 1989; Herbarium, in Madrid (MA). We noticed that for some collec- Bridson, 1998; Bridson & Verdcourt, 2003) and Flora of Trop- tions with label data at K the data did not correspond to that ical East Africa (Verdcourt, 1976; Bridson, 1988; Verdcourt & obtained from MA. We assume the data acquired from MA to Bridson, 1991). be correct. We did not succeed in obtaining data for most of the F. Casas collections. The collection numbers of both Carvalho and F. Casas specimens at K have an additional figure after a Diversity and conservation hyphen, which we think refers to the number of duplicates, but we are not certain about this. The checklist includes 58 genera, 147 species and three un- Under the heading ‘Representative specimens’ we cite named entities of Rubiaceae represented in the flora of the is- all the collections examined by us and also some collections lands of Bioko and Annobon. These numbers include six new referred to in the literature but not seen by us [marked n.v. for generic records and 26 new infregeneric records, found during not seen (non vidi)]. The material is cited following this order: the course of our investigations. In addition, we have enumer- specimens examined with locality data, specimens examined ated three potentially new taxa (Table 1). In Bioko, there are without locality data, specimens not seen. Localities are given 56 genera, 139 indigenous species and one introduced species in the format they appear on the label of the specimen cited; of Rubiaceae. we have not tried to modernize such spellings. We make ref- Of the seven species endemic to Bioko (Table 2), only erence to type specimens when they originate from Bioko and one is represented in the recent collections examined. Most of Annobon and include only synonyms relevant for the area. The the others have apparently been collected only once and may place of publication is given for accepted names but not for be rare or perhaps extinct. More data are needed to evaluate synonyms. Under the heading ‘Ecology’ are details of habit the conservation status of each of these endemic species. and habitat, again obtained directly from the specimen labels. Five of the seven endemics have Mildbraed collections It was not our intention to give a complete summary for each as their type specimens. These collections were held at the Rubiaceae of Bioko and Annobon 161 Bertiera racemosa (G.

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