Revision of Passiflora Subgenus Decaloba ... - Passion Flowers

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moth pollination. Detailed studies of the pollination biology of this species are
needed.
Pollination by hummingbirds is common in several groups of Passiflora, and
MacDougal (1994) hypothesized that dependence on hummingbirds for
pollination has arisen several times in the genus. He suggested that the
traditional reliance by taxonomists of Passiflora on flowers for plant classification
has led to the repeated recognition of hummingbird pollinated groups at
misleadingly high ranks. The molecular and morphological hypotheses
presented here suggest that the subgenus Chloropathanthus recognized by Killip
(1938) represents two independent shifts to hummingbird pollination, once in P.
lancifolia and P. macfadyenii and again in P. viridiflora. These species have
flowers characterized by an elongated androgynophore, an elongated
hypanthium, a reduced corona, and inodorous flowers. Passiflora lancifolia and
P. macfadyenii possess red flowers. Passiflora viridiflora has greenish yellow
flowers but the stems, stipules, tendrils, leaf margins and floral pedicels are
bright red. Passiflora viridiflora is most closely related to P. juliana, and P.
lancifolia and P. macfadyenii appear to be most closely related to P. pallida and
P. suberosa. Thus, characters of the flower resulting from a shift to hummingbird
pollination in these species are due to convergence.
Passiflora itzensis and P. xiikzodz have very unusual flowers (see Figs. 8.36
and 8.38), and their pollinators are unknown. The flowers have a greatly
elaborated corona with seven rows of filaments but completely lack a floral
nectary and do not produce nectar. Thus, an operculum that would cover and