Passion flowers are so named because of the religious meaning assigned to the various parts of the flowers structure, specifically, the crucifixion of Christ.
South American priests in the 16th century ascribed the five petals and sepals to the ten disciples sans Peter and Judas. The radial fringe to the crown of thorns and the stylized stigma, are the nails on the cross.
There are many colors and many types both hardy and tropical.
Apart from the unique characteristics of the flower Passifloras are desirable for their role as a host plant for butterflies. Many butterflies lay their eggs on the foliage and the caterpillars dine on the leaves. A mature Passiflora stand can harbor and maintain a large colony of larvae but a smaller potted specimen may need protection.