Humbertacalia C. Jeffrey is a genus native to Madagascar and Réunion characterized by its scandent habit, the discoid capitula, and the caudate anther bases. According to the present treatment, it comprises ten species, nine endemic to Madagascar and one species thriving in both Madagascar and Réunion. The new combinations Humbertacalia abbreviata (Humbert) Rabarim., Callm. & J. Calvo, comb. nov., stat. nov., H. apocynifolia (Baker) Rabarim., Callm. & J. Calvo, comb. nov., and H. diffusa (Baker) J. Calvo, Rabarim. & Callm., comb. nov., stat. nov. are established and nine other names are lectotypified. At the specific rank, the name H. voluta (Baker) C. Jeffrey is synonymized under H. apocynifolia comb. nov. and H. leucopappa (Bojer ex DC.) C. Jeffrey is synonymized under H. racemosa (Bojer ex DC.) C. Jeffrey. A detailed study of the type material of H. leucopappa at G revealed that the species was misinterpreted for a long time, despite the wide usage of the name. Revised nomenclature, diagnostic description, taxonomic discussion, conservation status and list of specimens examined are provided for all accepted species, in addition to an identification key and two illustrations.
Asteraceae, Senecioneae, Madagascar, Réunion, identification key, lectotypifications, new synonyms, new status, new combinations