Data from: New insights into floral morph variation in Passiflora incarnata L. (Passifloraceae) in Tennessee, U.S.A.

Passiflora incarnata is a functionally andromonoecious clonal wildflower,
native to the southeastern United States, whose primary pollinator is the
carpenter bee, Xylocopa virginica. While recent studies looking at
reproductive ecology in P. incarnata have classified flowers as one of two
morphs (male or hermaphroditic) based on stylar deflexion, preliminary
field studies conducted in Tennessee indicated there were five distinct
morphs present (three male, two hermaphroditic), supported by stylar
deflexion, floral size, and pistil development. The present study sought
to test the hypothesis that five distinct floral morphs are present in P.
incarnata by sampling 13 floral characters, and to document variation in
nectar constituents, volume, and concentration across the five morphs.
Five well-established individual plants were examined at three sites in
Cookeville, Tennessee. Two-factor permuted analysis of variance of 13
floral characteristics with floral morph and individual plants as factors
suggested that morph:plant interactions explained 6%, individual plant
explained 18%, and floral morph explained 36% of variation in floral
characteristics. Nectar sampling indicated that all morphs produced nectar
comprised exclusively of sucrose. Nectar volume generally increased with
floral morph size, while nectar concentration decreased. NMDS analysis
indicated that the five hypothesized morphs were supported as distinct,
with substantial overlap between the two largest morphs (4a and 4b). The
supported morphs are best distinguished by ovary width, ovary length,
style length, and stigma width. These findings support a hypothesis that
the morphs result from variation in developmental arrest during floral
ontogeny. The ecological implications of the five morphs and nectar
variation are considered for X. virginica with suggestions for additional
studies.