Revision of Passiflora Subgenus Decaloba ... - Passion Flowers

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supported P. pallida clade and the clade containing P. suberosa along with the
rest of the species from the supersection, indicating that there is gene flow, likely
resulting from hybridization, between P. suberosa and P. pallida. This gene flow
has likely obscured the distinctiveness of P. pallida and contributed to the broad
circumscription of P. suberosa.
All of the published chromosome counts of the species of Passiflora
supersection Cieca support x = 6 as the base chromosome number (Beal, 1969,
1971; Diers, 1961; Melo, Cervi & Guerra, 2001; Melo & Guerra, 2003; Snow &
MacDougal, 1993; Storey, 1950; Turner & Zhao, 1992). Individuals of Passiflora
suberosa ssp. litoralis from Argentina, Brazil, Australia, and New Guinea have
been shown to be polyploids (including triploid, tetraploid, and hexaploid counts)
(Beal, 1969, 1971; Melo & Guerra, 2003). However, Diers found the diploid
chromosome number of 2n = 12 in P. suberosa ssp. litoralis from Lomas de
Lachay, Peru. I have not been able to locate Diers' voucher specimens to
confirm his determinations, but based upon the collection locality alone (Diers,
1961), the plant that he sampled was likely an individual of P. suberosa ssp.
litoralis. Storey (1950) also counted the chromosomes of Hawaiian material of P.
suberosa. He found chromosome numbers of 2n = 24 and 2n = 36 in wild
populations of the species. He determined that the 36-chromosomal form was
likely an autotriploid derivative of the 24-chromosomal form. He did not describe
the plants that he sampled, but he noted that there were no conspicuous
morphological difference between the two chromosomal races. He found only
that the triploid race had slightly larger leaves and more anthocyanin