Hypericum /ˌhaɪˈpɪərɨkəm/ is a genus of 490 species of flowering plants in the family Hypericaceae (formerly often considered a subfamily of Clusiaceae). Hypericum is unusual for a genus of its size because a worldwide taxonomic monograph was produced for it by N.Robson (working at the Natural History Museum, London, UK, between 1977 and 2012).