Here we present Inosperma macrocarpa as new to science and the first record of I. afromelliolens from West Africa. Inosperma macrocarpa is nested in an Old World Tropical clade, based on a molecular phylogeny inferred from sequences of ITS, LSU, RPB2 and TEF1. Complete description and illustrations, including photographs and line drawings, are presented for the new species. Morphological and molecular analysis based on collections from Benin also confirm the presence of I. afromelliolens in West Africa. A toxicity analysis shows that neither species contain muscarine which lend further support to the hypothesis that the ability to produce muscarine is a derived trait in Inosperma.