Morphological characteristics of an understudied genus Oxyanthus, in Nigeria was studied using conventional methods. Species distribution within the area was also examined using data from herbarium specimens and field observations. Foliar micro-characters studied showed that the species are hypostomatic with irregular cells on the abaxial surface. Epidermal cells on adaxial surface were generally polygonal with exceptions in O. racemous where they were predominantly irregular and in O. unilocularis where there was a combination of irregular and polygonal cells. Trichomes (simple, unicellular) were only present on the abaxial surfaces of O. racemosus and O. subpunctatus and absent in others. Leaves were largest in O. unilocularis (38.0cm) and smallest in O. subpunctatus (9.9 cm). Pollen grains were largest in O. racemosus (PxE = 42.1x42.3µm) and smallest in O. gracilis (PxE = 28.9.1x29.6µm). However, numerical data analysis showed that O. gracilis and O. laxiflorus were the most closely related taxa, with similarity level of 72.6, while O. formosus and O. unilocularis were the most distantly related species (similarity level = 1). Oxyanthus species are characteristic of tropical lowland rain forest vegetation. Distributional studies showed that they species are confined to the forest zones of South-western Nigeria except O. racemosus and O. unilocularis which could also be found in the drier parts of the country. Although the population trend of the species studied could be said to be stable, the continuing decline of mature individuals is attributed to threats from logging and removal of forest cover for farming activities. We recommend a more comprehensive taxonomic study on the genus Oxyanthus and other related genera within the Rubiaceae, which will combine data from DNA analysis, morphology and ecology to further re-establish the existing relationship within and among taxa, and draw inference on species conservation in the Sub-Saharan African country. In short, the need for conservation of our rich but endangered flora is crucial, to checkmate complete loss of species.