Passion-flower

Passion flower (Passiflora; syn. Disemma Labill.) is a genus of about 500 species of flowering plants in the family Passifloraceae. They are mostly vines, with some being shrubs, and a few species being herbaceous. For information about the fruit of the passiflora plant, see passionfruit.

Biology
Most decorative passifloras have a unique flower structure, which requires a large bee to effectively pollinate (see photos below). In the American tropics, wooden beams are mounted very near passionfruit plantings to encourage Carpenter bees to nest. At the same time, the size and structure of flowers of different species of passiflora vary. Some species can be pollinated by hummingbirds and bumble bees, others by wasps, still others are self-pollinating. Passiflora species are used as food plants by the larva of the moth, Cibyra serta and many Heliconiinae (longwing butterflies). Notable among the latter are species like the Melpomene, Sara, and Rosina longwings.

The bracts of Passiflora foetida are covered by hairs which exude a sticky fluid. Many insects get stuck to this. Studies have suggested that this may be an adaptation similar to that seen in carnivorous plants. (Radhamani, et al)

Origin
The family Passifloraceae is found world wide, excluding Europe and Antarctica. Nine species are found in the USA. Passion flowers are found from Ohio to the north, as far west as California and south to the Florida Keys. Passion flowers are found in most of South America as well as China and Southern Asia (with 17 species), New Guinea, Australia (with four, possibly more species) and New Zealand with one monotypic member of the family.

Africa has many members of the family Passifloraceae, (the rather more primitive Adenia) but no Passiflora.

The purple fruited Passiflora edulis and the yellow fruited Passiflora edulis var. flavicarpa are widely grown in subtropical and tropical regions respectively, for their delicious fruits.

These forms of Passiflora edulis have been found to be different species. They occur in different climate regions in nature and bloom at different times of day. The purple fruited species is self fertile and the yellow fruited species, despite claims to the contrary, is self sterile. It requires two clones for pollenization.

Cultivation
During Victorian times the flower (which in all but a few species lasts only one day) was very popular and many hybrids were created using P. caerulea and P. alata and other tropical species.

Hundreds of hybrids have been named and hybridizing is currently being done extensively for flowers, foliage and fruit. A number of species of Passiflora are cultivated outside their natural range (where some have become established) because of their beautiful flowers. The passion fruit or maracujá vine of commerce, Passiflora edulis, is cultivated extensively in the Caribbean and south Florida and South Africa for its fruit, which is used as a source of juice.

Maypop (Passiflora incarnata), a common species in the southeastern US. This is a subtropical representative of this mostly tropical family. However, unlike the more tropical cousins, this particular species is hardy enough to withstand the cold down to -4°F (-20° C) before its roots die (it is native as far north as Pennsylvania and has been cultivated as far north as Boston.) The fruit is  sweet, yellowish, and roughly the size of a chicken's egg; it enjoys some popularity as a native plant with few pests and edible fruit. As with other passifloras, it is the larval food of a number of butterfly species and is important to local wildlife. Carpenter bees figure as important pollinators of maypops.

Banana poka or Curuba (Passiflora tarminiana), originally from Central Brazil, is an invasive weed, especially on the islands of Hawaii, where it is spread by feral pigs eating the fruits. It overgrows and smothers stands of endemic vegetation, mainly on roadsides. Its fruits are edible, but not as much sought-after as maracujá.

Chilean passiflora, (Passiflora pinnatistipula) grows in the Andes, from Venezuela to Chile, between 2500 and 3800 meters altitude, and in Coastal Central Chile, in where is an endangered vine from humid woody Chilean Mediterranean forests.

Many cool growing Passiflora from the Andes Mountains can be grown successfully for their beautiful flowers and fruit in cooler Mediterranean climates, such as the Monterey Bay and San Francisco in California and along the Western Coast of the U.S. into Canada.

Most species have elongated fruit from two to eight inches long and an inch to two inches across depending upon the species or cultivar. P. pinnatistipula has a round fruit unusual in the Tacsonia group, which is typified by P. tarminiana and P. mixta with their elongated tubes and brightly red to rose colored petals.

Medical and entheogenic uses
Passiflora incarnata leaves and roots have a long history of use among Native Americans in North America. Passiflora edulis and a few other species are used in Central and South America. The fresh or dried leaves are used to make an infusion, a tea that is used to treat insomnia, hysteria, and epilepsy, and is also valued for its painkilling properties. It has been found to contain beta-carboline harmala alkaloids which are MAOIs with anti-depressant properties. The flower has only traces of these chemicals, but the leaves and the roots of some species contain more and have been used to enhance the effects of mind-altering drugs. Once dried, the leaves can also be smoked.

Passion flower also may be effective for anxiety disorder, but further studies are needed. 

The name
"Passion" does not refer to love, but to the Passion of Christ on the cross. In the 15th and 16th centuries, Spanish Christian missionaries discovered this flower and adopted its unique physical structures as symbols of Crucifixion. For example: the radial filaments which can number more than a hundred and vary from flower to flower represent the Crown of Thorns. The ten petals and sepals represent the ten faithful apostles. The top 3 stigmata represent the 3 nails and the lower 5 anthers represent the 5 wounds. The flower has been given names related to this symbolism throughout Europe since that time. In Spain, it is known as Espina de Cristo (Christ's Thorn). In Germany it was once known as Muttergottes-Schuzchen (Mother-of-God's Star).

In Israel they are referred to as clock-flower (שעונית). In Japan, they are known as clock-faced flowers, and recently have become a symbol for homosexual youths. In North America they are also called the Maypop, the water lemon, and the wild apricot (after its fruit). Native Americans in the Tennessee area called it ocoee, and the Ocoee River and valley are named after it.