Revision of Passiflora Subgenus Decaloba ... - Passion Flowers

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Vegetatively, P. viridiflora and P. juliana are very similar, and the most obvious
difference between them is the size and shape of their stipules. However, P.
viridiflora also differs from P. juliana in its adaptations for hummingbird pollination
including: vegetative parts that are commonly accentuated with or entirely bright
red, a greatly elongated androgynophore that far exceeds the length of the
stamen filaments, no inner coronal filaments, a very narrow limen floor, wide
floral nectary, long operculum that is not incurved at the margin but erect and
lays against the androgynophore, fused sepals that are greatly elongated, pollen
that is presented laterally, and a sulcate floral nectary floor.
MacDougal, in an unpublished paper on the morphology and vascular
anatomy of the node of P. viridiflora, found that the nodal anatomy with regard to
the vascular tissue of this species is consistent with the view that the tendril is a
modified axillary branch or shoot system, as established previously by Cussett
(1968). MacDougal also concluded that the close association of the
vascularization of the flower peduncles with the tendril point to the fact that the
tendril is part of an inflorescence.
Limited artificial self-pollinations of P. viridiflora performed by MacDougal in
the greenhouse failed to produce fruits. However, MacDougal was able to
successfully cross P. viridiflora with P. megacoriacea, P. mcvaughiana, P.
pallida, P. trinifolia, P. filipes, and P. macfadyenii.
On an herbarium specimen collected by W.L. Forment (1125), he indicated
that P. viridiflora is utilized by hummingbirds, which is consistent with its floral
morphology and lack of floral fragrance.