Novelties in Psiadia Jacq. ex Willd. (Compositae) from Madagascar and Comoros

Madagascar and the other islands of the western Indian Ocean are the foremost center of species diversity of the genus Psiadia Jacq. ex Willd. (Compositae, Astereae). Revising the material housed in the historical herbaria P-JU and P-LA, we realized that the name P. madagascariensis (Lam.) DC., based on Lamarck’s name Conyza madagascariensis Lam., was misinterpreted and should be the priority name for the widely used Psiadia altissima (DC.) Benth. & Hook.f. ex B.D. Jacks. To avoid further misinterpretation, the types of the names Conyza glutinosa Lam. [accepted as Psiadia glutinosa (Lam.) Willd.] and Glyphia lucida Cass. [accepted as Psiadia lucida (Cass.) Drake] are discussed and clarified. In this frame, lectotypes are designated for six names. Moreover, the species P. lucida is recorded for the first time in the Comoros (Grande Comore). Finally, a new disciform species of Psiadia from Madagascar, i.e., Psiadia salicifolia J. Calvo & Callm., sp. nov., is described and illustrated.