Passion flower refers to vines in the genus Passiflora—flowering plants known for their showy flowers. The plants were named for the passion of Christ, because the flower structure seemed symbolic of Jesus' scourging, crowning with thorns, and crucifixion. Passion flowers are native to tropical and sub-tropical America. However, a number of species of Passiflora are cultivated outside their natural range (where some have become established) because of their beautiful flowers.