Likeliest possibilities are the native Maypops, Passiflora incarnata, and the blue passionflower, P. caerulea.

A letter received from Elvin McDonald mentions that seed of Passiflora caerulea, the blue passionflower, is sold in the Signature Seed offering of the Brooklyn Botanic Garden.

Hirt's Gardens offers both seeds and mature plants of Passiflora in several varieties, including the Scarlet passionflower, the Sweet Granadilla, the Sweet Calabash, and the Blue passionflower, as well as an edible variety.

Passiflora caerulea (blue passion flower, common passion flower) is a species of flowering plant native to South America (Argentina, Paraguay, Uruguay and Brazil).