Revision of Passiflora Subgenus Decaloba ... - Passion Flowers

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central lobe is ovate and never narrowed at the base. Passiflora macfadyenii
possesses distinctly trilobed leaves with the lateral lobes commonly more than
half the length of the central lobe, and the central lobe is obovate with a distinctly
narrowed base similar to that in P. juliana and P. viridiflora. The pedicels in P.
lancifolia are greater than 2.3 cm long, whereas those of P. macfadyenii rarely
exceed a length of 1.8 cm. The floral nectary of P. lancifolia is the widest in the
supersection, greatly exceeding that of P. macfadyenii. The outer coronal
filaments are connate and often not adnate to the sepals or barely so in P.
lancifolia, whereas those of P. macfadyenii are distinctly adnate to the sepals.
Passiflora lancifolia often has two rows of coronal filaments (rarely with one row
or a poorly developed inner row) and P. macfadyenii lacks an inner coronal row
(with a poorly developed second coronal row seen in one flower from a plant in
cultivation, i.e., MacDougal 452 - cultivated from cuttings of Thomas 2032). The
fruits of P. lancifolia and P. macfadyenii are distinct, with P. lancifolia having
globose fruits and P. macfadyenii possessing fusiform fruits. The habitats of the
species are also different with P. lancifolia growing in tropical lower montane mist
forests at 850-1220 m and P. macfadyenii found in tropical dry forests at 200-310
m.
Benson et al. (1975), in a study of the coevolution of plants and herbivores,
reported that Dryas julia is an herbivore of P. lancifolia. However, the authors
relied upon the keys in Killip (1938) in making their botanical determinations, and
at the time of Killip's monograph, P. macfadyenii had not been described.