Passiflora Supersect. Pterosperma (L. Gilbert & J. M. MacDougal) J. M. MacDougal & Feuillet. Passiflora 13(2): 37. 2003 [2004]. Basionym:
Passiflora sect. Pterosperma L.E. Gilbert & J. M. MacDougal. Novon 13(4): 459. 2003.
Medium-sized woody vines to canopy lianas; stem and abaxial surface of leaves
puberulent as seedlings, the erect trichomes sometimes glandular, lightly puberulent to
glabrous at maturity; stems terete, pith chambered, posture of shoot tip cernuous;
stipules extremely reduced, caducous; petioles (0)1–11-glandular; laminas narrowly
ovate to (very) widely ovate, conspicuously peltate in one species, with conduplicate
ptyxis, entire, acute to abruptly acuminate (rarely obtuse), variegated adaxially or not
in juveniles, usually glaucous abaxially, laminar nectaries present submarginally, or
absent; prophylls of vegetative bud 2, colateral; tendrils in seedlings distally swollen
and adhesive in at least one species; peduncle 1 per node, bearing both a tendril and 1or
2 pedicels, these often branched so that the inflorescence is (1)2–6-flowered, the
tendril expressed in the inflorescence sometimes aborting, the common peduncle sometimes
reduced to nearly nothing so that the pedicels appear to arise from the leaf axils; bracts
3 per first order pedicel, 0.8–3.5 mm long, narrowly triangular to linear-lanceolate;
floral stipe (pedicel distal to articulation) conspicuous, 9–42 mm long; flowers white
with a yellow or white outer corona, this with a purplish red band or not; sepals and petals
subequal, 17–25 mm long, coronal filaments in (2)3–4 series, the outermost
9–20 mm long, the inner 1.5–8 mm long; operculum plicate; androgynophore
7–14 mm; ovary puberulent to densely pubescent; fruit 4–6 cm in diameter,
conspicuously stipitate, inflated, the pericarp very thin and leathery to parchment-like;
seeds 6–12 mm x 5–11 mm, the testa reticulate in center and surrounded by striate
wings with erose to laciniate margins, the chalazal beak antiraphal; pollen 6-colporate;
chromosome number n=9 (one species known). Germination epigeal.
The four rather similar species of supersection Pterosperma are uncommon lianas of
primary moist to wet tropical forest. Three of the four are known to be the sole host/food
plant in their geographical area for the larvae of the uncommon heliconiid butterfly,
Eueides lineata (Mallet and Longino, 1982; Knapp and Mallet, 1984; Meerman, 1999).
The stipules of each species are minute and deciduous, the new growth is cernuous, the
minute laminar nectaries are submarginal when present, and the inflorescence type is the
primitive state for the genus, i.e., a pedunculate dichasial cyme with the central pedicel
modified to be a tendril. The white flowers have the characteristics of a bee-pollination
syndrome, and indeed, one is known to be bee-pollinated. Each species has similar unusual
marginally winged seeds, hence the name of the section. The possible function of the wings
is unknown, but may related to the wide aril covering each seed or how it is removed during
dispersal. The arils and the shape, color, and persistence of the fruits are known for two
of the four species of this section, and suggest dispersal by frugivorous bats (Gilbert
and MacDougal, 2000). [Images under construction].