Wednesday, February 10, 2010

Tropical passion flowers and passion fruits. by Jorge Bogantes Montero, volunteer

Published in the U.S. Botanic Garden Newsletter "As the Garden Grows", Volume 7, Number 3/ Summer 2009

If a pretty flower or a tropical fruit flavor could transport our minds to the tropics, passion flowers/passion fruits would be some of the chosen ones. When hiking through the tropical rainforest trails of Costa Rica (where I am from), the sighting of a Grape-leaved Passion Flower (Passiflora vitifolia) used to bring a spectacle of exquisiteness which often jumps out of the apparent deep green monotony of these amazing forests. The contrasting splash of bright colors and exotic shapes of the passion flowers are normally a good reason to stop and behold. After pollination, these plants produce the extraordinary passion fruits or granadillas, which are almost all edible though not all the species produce fruits that are palatable enough to be eaten. The edible parts of passion fruits are the arils (the pulp covering the seeds) and the mesocarp (the fleshy wall underneath the peel where the seeds are attached). However, in the commercial species only the aril is edible, since the mesocarp is too crusty and insipid. The sweet/tart freshness of these fruits provides an excellent remedy for hot sunny days, perhaps, anywhere in the world. Even though Passiflora, which is the genus encompassing all the species of passion flowers/passion fruits, are not restricted to the tropics; the most important species are, at least economically speaking. There are more than 500 species of passion flowers of tropical and subtropical origin, of which 90% are native to the Americas. Here are the number of species for three selected countries: 9 in the USA, about 50 in Costa Rica, and, more than 200 species in Brazil. There is at least one local species of passion flower with edible fruits around the DC area, Passiflora incarnata, this species is known as ‘Maypop’.

Some passion flower species are important food crops and ornamentals. In Costa Rica, these plants are widely used in butterfly farming as host plants for the beautiful heliconian butterflies, whose larvae feed on the foliage of these plants. The outstanding beauty of these ‘exotic’ flowers has given them the suggestive name. Although, some people are likely to be surprised when they learn about the actual origin of this common name. Passion flower (or Passiflora in Latin) does not refer to any sort of love lore; but rather has a religious origin. When catholic Spaniards arrived to what today is Latin America, they named it passion flower in reference to the symbols of the passion of Christ. The flowers’ corona -the colorful threadlike filaments set in a circle around the flower’s reproductive organs- represents the crown of thorns said to have been placed on Jesus’s head. The style (female flower part) which is divided into three parts, denotes the three nails; the five stamens (pollen-bearing parts) stand for Christ’s five wounds; and the length of time the flower blooms, usually around three days, corresponds to the time between the crucifixion and the resurrection.

A South American species of passion flower, Passiflora edulis, known as Maracuyá in Spanish or Maracujá in Portuguese, produces the popular passion fruits that are consumed throughout the world. This is the one you are likely to get at most grocery stores, ice cream shops, bars, and restaurants. The fruits can be either purple or yellow colored. The purple fruits originally come from Brazilian populations. This passion fruit has an excellent flavor suitable for many kinds of beverages, smoothies, gelati, and cocktails. When buying these fruits at the supermarket attempting to make your own goodies from scratch, you have to bear in mind that the useful part of the fruit is the aril, namely, the somewhat jelly-textured pulp covering each seed and not the seeds themselves! Blending the seeds excessively with the blender will make your juice taste astringent and give an unappealing color to it. Other species with popular passion fruits are: Giant Granadilla (Passiflora quadrangularis) -which the USBG displays at the Conservatory’s Plant Exploration Room-, Sweet Granadilla (Passiflora ligularis), the Banana Passion Fruit (Passiflora mollissima), and a few other South American species. However, all these species are virtually impossible to find in most grocery stores in the U.S., or at least in the DC area.

Passion flowers are not just pretty edible plants; they also have an important medicinal value, at least in the more traditional herbal medicine. Nearly all the plant parts of some species are considered to be effective to treat diseases related to the central nervous system. The plants are also used to combat gastrointestinal problems, pulmonary problems, among others.

Furthermore, passion flowers are not just meant to feed, delight or heal humans! These plants have coevolved with a plethora of organisms in their native habitats. The ecological relationships between these plants and many animals are rather complex. Therefore, all the unique features of passion flower plants that draw our attention (unusual shapes, pretty colors, good flavors, smells, etc.) are the result of this intricate coevolution. As mentioned above, leaves are eaten by butterfly larvae; the plant’s chemical compounds protect these larvae from predators simply by making them toxic! The flowers are usually pollinated by hummingbirds, bees, butterflies, wasps, and bats; but some species do not need the ‘pollination services’ of these animals since they can self pollinate. Passion flower plants have unique structures known as extrafloral nectaries, these are nectar-producing glands located at the leaf stalks and at the leaves edges. The purpose of the extrafloral nectaries is to attract and benefit predatory insects with yummy treats; usually ants that defend the plant from herbivorous insects. I encourage all the readers to explore and enjoy these amazing flowering plants, not only the tropical species, but also the species native to North America, and, more importantly to preserve them!

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