Nomenclature of Isotrema, Siphisia, and Endodeca, and their related infrageneric taxa of Aristolochia (Aristolochiaceae)

The circumscription of Aristolochia L. s.l. (Aristolochiaceae) and its infrageneric taxa has been variable. In some classifications, Aristolochia subg. Siphisia (Raf.) Duch. has often been recognized, but the author citation of the subgenus is incorrect because the generic name Siphisia Raf. is superfluous and illegitimate. In the course of reviewing this author citation, we noticed that the nomenclature for the related genera Isotrema Raf. and Endodeca Raf., and the subtribes Aristolochiinae H.Huber and Isotrematinae H.Huber requires reconsideration. Herein, we review the nomenclatural history of Isotrema, Siphisia, Endodeca, and related genera. We also discuss the related infrageneric taxa of Aristolochia and the subtribes Aristolochiinae and Isotrematinae. Consequently, we confirm that the types of Isotrema and Endodeca and their author citations are I. sipho (L'Her.) Raf. ex B.D. Jacks. and E. hastata Raf., respectively. In addition, we correct the author citation for Aristolochia subg. Siphisia to (Duch.) O.C.Schmidt. Furthermore, the names Aristolochiinae and Isotrematinae are found to have been invalidly published, since they lacked a Latin description or diagnosis, or reference to earlier validly published names.