The putatively closely related cactus genera of Coleocephalocereus, Micranthocereus, Cereus, Monvillea, and Stetsonia have a wide range in specialization of reproductive portions of the shoot, from cephalium to pseudocephalium to no specialization. After briefly summarizing the shifting uses of the terms ‘cephalium’ and ‘pseudocephalium’, I provide gross morphological evidence that Coleocephalocereus purpureus has a true cephalium that is formed of a continuous swath of bristles and hairs, with its underlying thick cortex of parenchyma replaced by a narrow layer of cork. By contrast, Micranthocereus streckeri has a pseudocephalium composed of nothing more than larger hairier areoles in which the underlying epidermis is still photosynthetic and the underlying cortex is still a thick layer of parenchyma without any noticeable cork.