As currently circumscribed, Passiflora section Cieca is characterized by its small, apetalous flowers with the filaments of the corona mostly in one or two series and by reticulate seed coats. The rapidly evolving species of the section are primarily distributed in the southern United States, Mexico, Central America, South America, and the Caribbean. One species is also found in the Old World (likely resulting from recent human introduction). Section Cieca contains two problematic species, P. suberosa and P. coriacea. Since Linnaeus first named P. suberosa in his Species Plantarum, taxonomists have disagreed about the circumscription of the species and, as a result, over 60 synonyms exist for it. Our preliminary analysis of the herbarium specimens of P. suberosa indicate that this variable species has likely served as a "taxonomic garbage can" for entities that cannot be assigned to any of the other members of the section. Passiflora coriacea is also a species that exhibits marked morphological variation over its distribution from eastern Mexico to northern South America, containing several distinct entities. Morphology along with nucleotide sequence data from GBSSI (waxy), ITS-1, ITS-2 and the intervening 5.8S region of the nuclear genome were used for the phylogenetic analysis of the species within Passiflora section Cieca (Passifloraceae). Preliminary morphological and molecular data indicate strong support for the monophyly of section Cieca and indicate that P. suberosa and P. coriacea, as currently circumscribed, are likely non-monophyletic groups of cryptic species. Morphological data suggest that the mainland entities of P. suberosa are more closely related to other mainland species in the section than to those entities of P. suberosa from the Greater Antilles and Galapagos. Furthermore, morphology indicates that hummingbird pollination has evolved twice within section Cieca.

Key words: GBSSI, ITS, morphology, Passiflora, phylogeny, section Cieca