A revision of Passiflora L. subgenus Decaloba (DC.) Rchb. supersection Cieca (Medik.) J. M. MacDougal & Feuillet (Passifloraceae)

Passiflora subgenus Decaloba supersection Cieca is a monophyletic group of herbaceous to woody climbers found in subtropical and tropical regions of the world. The 19 species recognized here are primarily distributed in the southern United States, Mexico, Central America, South America, and the Caribbean. Two species, P. suberosa and P. pallida, are also naturalized in various regions of the Old World. The species of the supersection are recognized by their small, apetalous, usually greenish flowers with the filaments of the corona mostly in two series. The plants commonly lack c-glycosylflavones but possess flavonol 3-O-glycosides. The supersection contains two problematic species complexes, P. suberosa and P. coriacea. Phylogenetic relationships within supersection Cieca are investigated by means of phenetic and cladistic analyses of morphological and molecular (ITS 1 & 2) characters. The morphological and molecular data sets were analyzed separately because of incongruity due to taxon sampling and the complicated evolutionary history of entities within the P. suberosa complex. All analyses confirm the monophyly of the supersection. They also show that the P. suberosa complex is a non-monophyletic group of cryptic species, and inter-taxic hybridization and polyploidy have contributed to the confusing and complex pattern of variation evident within the group. Four taxa that were formerly included in this complex are recognized: P. pallida, P. suberosa subsp. suberosa, P. suberosa subsp. litoralis, and P. tridactylites. On the basis of molecular and morphological data, three species from the P. coriacea complex are recognized: P. coriacea, P. sexocellata, and P. megacoriacea. A key, detailed descriptions, distribution maps, and illustrations are included in the revision. Pollination, dispersal, and herbivory of the group are reviewed. The distribution and ecology of the species within the supersection are also discussed.