Recent results have demonstrated that the genus Desmanthus is non-monophyletic because the genus Kanaloa is nested within it, with a single species, Desmanthus balsensis placed as sister to the clade comprising Kanaloa plus the remaining species of Desmanthus. Here we transfer D. balsensis to a new segregate genus Mezcala, discuss the morphological features supporting this new genus, present a key to distinguish Mezcala from closely related genera in the Leucaena subclade, and provide a distribution map of M. balsensis.