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on the Mucuna species

I saw an interesting flowering vine growing in Japan, and I am wondering what it is and if I can grow it here in Seattle. It has very dark purple (almost black) claw-like flowers and fuzzy stems. Is it purely ornamental, or does it have other uses?


The plant you saw is a species of Mucuna, probably Mucuna pruriens or Mucuna nigricans. M. pruriens has various common names: velvet bean, and cowhage or cowitch (from the Hindi name, kiwach, which means “bad rubbing,” and refers to the extreme itching—pruritus–that contact with the stinging hairs on the pods causes). You might be able to obtain seeds and grow it here as an annual, but it prefers tropical regions and is native to southern China and eastern India.

The plant has uses in Ayurvedic medicine and is also considered an analog of the hallucinogenic ayahuasca. According to the scientific article “The Magic Velvet Bean of Mucuna pruriens (Lampariello et al. Journal of Traditional Complementary Medicine, 2012 Oct-Dec), the pods are used as a vegetable for human consumption, and its young leaves are used as animal fodder in parts of Asia, Africa, the Pacific Islands, and America.

Strangely, the beans are sometimes used with malice, to cause discomfort, as this information from the Centers for Disease Control explains:
“On October 6, 1985, a Paterson, New Jersey, Fire Department ambulance responded to a call reporting two people with severe pruritus. On arrival, the two emergency medical technicians (EMTs) found a Spanish-speaking couple living above a beauty salon who described severe itching, which they attributed to ‘voodoo beans’ found in their beds. They displayed several fuzzy bean pods. Soon after their arrival, the EMTs developed pruritus. All four individuals went to an emergency room complaining of itching and skin discomfort. On examination, both members of the couple had erythematous macular rashes on their extremities and bodies; the EMTs had rashes on their arms. There were no respiratory problems. Because of the unknown etiology of the symptoms, two were given epinephrine injections; the others received antihistamines and topical steroid cream. Symptoms resolved within 1-2 hours of treatment. The admitting nurse, who put an arm around one patient, developed a pruritic erythematous area on her inner forearm approximately 20 minutes later. This resolved an hour after washing her skin with soap and water. A policeman who went to the apartment and a worker who collected trash outside the following day also developed itching and received similar emergency-room treatment. Patrons and employees of the shop below and neighbors of the couple had no similar symptoms over the 2-day period.”

If you do decide to grow this interesting plant, only handle it while wearing substantial gloves.

The seeds of some species of Mucuna (those called “sea beans”) are used in making jewelry. Here is an excerpt from Wayne’s Word (a natural history website):
“[the flowers] are pollinated by night-flying bats that sip the sweet nectar and transfer pollen from one plant to another. After pollination, the ovary of each flower develops into a legume pod containing several large seeds resembling miniature hamburgers. They have a hard, thick, woody seed coat which makes them impervious to water. Internal air cavities also make them buoyant in water. The conspicuous, dark, central attachment scar (hilum) produces the layered appearance, and their superficial resemblance to a miniature hamburger. Sea beans are washed down gullies and creeks where they are carried into rivers that eventually flow into the Atlantic or Pacific oceans. The buoyant seeds drift for months (or years) at sea, eventually washing ashore on the sandy beaches of a distant continent or tropical island. They are often collected and polished by natives and made into lovely necklaces and bracelets.”