Ixchelia, a new genus of Violaceae from Mexico and Mesoamerica

Ixchelia, a new genus of Violaceae, is described and illustrated, and new combinations are made for its two species, Ixchelia mexicana and Ixchelia uxpanapana, which are transferred from Hybanthus and Rinorea, respectively. In previous molecular phylogenetic studies, both Hybanthus and Rinorea have been shown to be polyphyletic, necessitating the erection of several genera for the constituent clades. Our recognition of Ixchelia as a distinct genus is based on morphological data and molecular phylogenetic evidence, both of which support its monophyly and its significant divergence from related genera. The new genus is most closely related to the Hawaiian endemic genus Isodendrion and the New World genus Pombalia, but it differs from them by having one to several flowers per inflorescence, a weakly zygomorphic corolla, the basal portion of the petals not fused, the stamen filaments fused into a tube, and the fruits containing three subspherical-ovoid seeds per capsule.