Allenanthus was a genus of flowering plants in the family Rubiaceae but is no longer recognized. It has been sunk into synonymy with Machaonia.[1]
Allenanthus was named by Paul Standley in 1940 in Annals of the Missouri Botanical Garden.[2] It was named in honor of Paul Hamilton Allen (1911-1963).
Until 2004, two species had been recognized, but fieldwork has shown that there is a continuum of variation between them.[3]
Comparisons of morphological characters and DNA sequences have shown that Allenanthus is embedded in Machaonia. This was confirmed by a molecular phylogenetic study of the subfamily Cinchonoideae in 2010.[1] Because of these results, Allenanthus is no longer maintained as a separate genus.