Studies on Mexican Cactaceae. V. Taxonomic notes on Selenicereus tricae

Selenicereus tricae is a poorly known species from Belize, Guatemala, and Mexico. We present a morphological and anatomical description of this plant and provide data on its habitat and geographical distribution. In addition, we discuss its taxonomic affinities with S. inermis, S. wercklei, and S. rubineus, its hypothetical closest relatives. Selenicereus tricae has already been combined with S. inermis, as subsp. tricae, and two new combinations are proposed here: S. inermis subsp. rubineus and S. inermis subsp. wercklei. The presence in S. inermis subsp. tricae of diagnostic morphological and anatomical features of Selenicereus and Hylocereus suggests that these two genera should probably be merged.