Heterophylly is frequent in Dendrophthora and Phoradendron, and may take many forms. The concepts prophyll, cataphyll, and scale-leaf are briefly discussed and defined as to usage in the Phoradendreae. Various morphological details of patterns of heterophylly, flower orientation and seriation, fusion of prophylls, phyllotaxy, sex distribution and inflorescence position are traced as far as the available material permits. A typology of inflorescences in these two genera is proposed, based on flower seriation. Anatomical observations on a few species of both genera have revealed striking and unsuspected structural differences between the inflorescences of some seemingly related species, but also similarities which cross the intergeneric boundary. The discovery of “extra-stelar” vascular proliferations in some species of both genera is of particular interest.