Atalahy, A.M., F. Rakotonasolo, S. Andriambololonera, M. Rabarimanarivo, H.L. Ranarijaona & S.G. Razafimandimbison (2020). A new name in the Malagasy tribe Vanguerieae (Rubiaceae). Candollea 75: 71–73. In French, English and French abstracts.
A variety of the Malagasy genus Canthium Lam. (Rubiaceae, Vanguerieae), Canthium perrieri var. louvelii Cavaco, is transferred to the genus Pyrostria Comm. ex Juss. because, like the typical variety already transferred in this genus, it shares its distinctive characters (inflorescences or solitary flowers involucrate). This taxon is further raised to species level, as it is morphologically distinct from Pyrostria perrieri (Cavaco) Razafim. et al. We provide the necessary new replacement name: Pyrostria orientalis A. Atalahy, Rakotanas. & Razafim., since the epithet louvelii is already occupied in Pyrostria.