List of Coffea species

The Specific Case of Psilanthus Species:

Coffee trees (Coffea genus) are woody plants belonging to the Rubiaceae family. Within this family and, in particular, the Coffeeae tribe, the position of the genus Psilanthus appears problematic because for a long time, it was considered as "false coffee trees." Consequently, they are nearly absent from the world's main living collections. Psilanthus, present on the African continent, Asia (India, Sri Lanka, tropical and South-East Asia), and Oceania (Northern Australia) but absent from the islands of the West Indian Ocean (Madagascar, Mascarenes, and Comoros), constitutes the closest phylogenetic group to Coffea (Robbrecht and Manen, 2006). Its status, established by Hooker (1873), confirmed by Chevalier (1947) and Leroy (1981), accepted by Stoffelen (1998), Khumar et al. (2008), has been refuted by Davis et al (2011). Thus, according to the latter proposition, coffee trees are represented by the 103 species of the genus Coffea (including the group of Baracoffea, endemic to the west coast of Madagascar) and the 21 Psilanthus species (see distribution map for each species); the new genus being called Coffea (introducing a possible source of confusion). In this database, we decide to present the species as before Davis et al (2011), but with the new name as synonyms to avoid any source of confusion. This doesn’t mean indeed that the proposition of Davis et al (2011) was refuted here.

Coffea: Multiple Sources of Name Confusions:

Another source of confusion is the justified or unjustified acceptance of synonymies. While it is generally accepted that Psilanthus minor is, in fact, P. sapinii or that Coffea vaughanii is C. myrtifolia, the synonymies of some Malagasy species reported in Davis et al (2006) remain problematic. However, these species appear under their original name in living collections and in various works. To avoid any confusion, we have chosen here to list all the species that have been described, to indicate synonymies where they exist and to treat all species individually. In addition, some species collected in the 1980s (Anthony et al. 1985, de Namur et al. 1987) have still not been described although they have been the subject of morphological and genetic studies (Bontems, 1990; Groell 1991, Baranski 1997, Hamon et al. 2017; Guyeux et al., 2019). They are maintained in the living collections of Côte d'Ivoire and Reunion Island. Finally, if 124 species were formally identified, 141 taxa could be taken into account (Couturon et al. 2016) and considered here. Most of these species are outcrossing species, with the exception of C. arabica (self-compatible and mostly self-fertilization), C. anthonyi, and C. heterocalyx for Coffea strictu-sensi and two species in the Psilanthus group.

Protection Needed for Coffea Species:

Davis et al (2006), considering only the "ex-Coffea" species, classified 14 (8 Malagasy and 6 African) as almost endangered, 23 as vulnerable (8 Malagasy, 2 Mauritian, and 13 African), 38 as endangered (30 Malagasy, 2 Mauritian, and 6 African), and 19 as seriously threatened (12 Malagasy and 7 African). There is no doubt that 12 years later, this observation has only worsened (Davis et al., 2019). Another observation concerns the protection of these species. The three largest living collections of wild coffee trees contain only 54.6% of the species. Two of these ex situ collections (located in the research station of the Centre National de Recherche en Agronomie de Divo, Côte d'Ivoire, and the Centre de Ressources Biologiques (CRB) of Bassin-Martin in Reunion Island are almost redundant in terms of the wealth of African species. However, the CRB in Bassin-Martin stands out from the others due to the presence of species collected in Reunion Island, Mauritius, and Mayotte by E. Couturon and collaborators in 2010. The third, located in the research station of the National Centre for Applied Research for Rural Development (FOFIFA) in Kianjavato, Madagascar, is unique. It includes the majority of Madagascar's endemic species with the exception of species (ex Baracoffea) endemic to the west coast of Madagascar. These species remain outside of any ex-situ collection.