Revision of Eulophia (Orchidaceae) in Nigeria, Cameroon, Equatorial Guinea, Gabon, and the Republic of the Congo

Background and aims – The genus Eulophia (Orchidaceae) is revised for Nigeria, Cameroon, Equatorial Guinea, Gabon, and the Republic of the Congo. The aims are: to present a morphological characterization of the main vegetative and reproductive features of Eulophia to clarify the delimitation of the taxa within the genus in the studied countries; to provide an updated identification key and an updated checklist of the genus with nomenclatural data, distribution maps, ecological information, and preliminary conservation status. This revision may serve as a basis for future studies of the genus in other regions of Africa. Material and methods – Relevant material kept in BM, BR, FHI, HBG, K, MA, P, and WAG was examined, using standard practices of herbarium taxonomy. Vegetative and reproductive structures were analysed. MapMaker was used to produce the distribution maps. Key results – A total of 24 species are recognised in the study area. The variability of perennating organs, leaves, sepals and petals, lip (including ornamentation), spur, and anther cap are described and depicted, and were found to be informative for species recognition. A taxonomic treatment is given with an identification key, synonymy, distribution maps, preliminary conservation status, and specimen citations. Eulophia galeoloides is neotypified, E. brevipetala, E. leonensis, E. penduliflora, and Lissochilus elatus are lectotypified. According to our study, we consider E. parvula a synonym of E. pyrophila. E. sordida is considered as a doubtful species in the study area.