If a sea bean could tell you its story you would hear about tall tropical forests, streams and rivers, trips in ocean currents, time spent swirling in an ocean eddy with other floating objects and an eventual landfall on a beach in the sea wrack. Beach or sea wrack is the line of debris, usually dominated by Sargasso seaweed, deposited on the beach at the tide line.
Sea beans, also called drift seeds, are quite diverse; most are seeds from tropical vines or trees and others, such as nickernuts, also called nickerbeans, are from seaside plants. All are seeds, but not all are beans (in the bean family). They are all well armored and float. The hard outer shell protects the seed which has evolved to sprout in the appropriate habitat. Air pockets help the seeds float and some seeds may not float in fresh water, but once reaching the more dense sea water they join the floating debris.
Hamburger beans are the quintessential sea bean and are often found on Caribbean beaches. There are three species of this bean in the Caribbean and they look very similar, but for our purposes we can call them hamburger beans, donkey eyes or ‘ojo de buey[‘ (bulls eyes- because of its resemblance to the eye of a bull). Caribbean hamburger beans come from vines that grow in lush tropical forests and are often pollinated by bats. There are many species of hamburger beans worldwide and currents carry them to tropical beaches worldwide. I have found the hard pods while hiking in the forest in Grenada and Trinidad and have found the beans on beaches in the Bahamas, Eastern Caribbean as well as in Los Aves in Venezuela. Hamburger beans are thought to bring good luck to the finder. They polish nicely and are often used for necklaces and other jewelry.
Sea hearts are larger than hamburger beans and will almost fill your palm with their shiny wood like heart shape. Sea hearts are the seed of the monkey ladder vine, which grows in wet lowland tropical forests of the Caribbean, Central and South America. The vine is flattened and ribbon like in a long chain of S curves that appear perfect for a monkey or sloth to climb. The seed pods can reach one to two meters in length, the longest of any legume. The seed pods disintegrate in the rain and the seeds fall to the forest floor. Rains wash the seeds, which are very buoyant and resistant to decay, into the streams and rivers and where the sea heart starts its life as a sea bean. They can drift for months or years to distant continents or tropical islands. Christopher Columbus was intrigued by the sea hearts he found on the beaches of the Azores off the coast of Portugal, where this bean is called "fava de Colom" or ‘Columbus bean’. Sailors have long used sea hearts a good luck charm.
The uncommon, but treasured Mary’s bean comes from a tropical vine or liana in the morning-glory family. This seed has a distinctive cross on one side of the seed and was named for the Virgin Mary. The vine grows only in Mexico and Central America, so it is easy to pinpoint the distance the bean has traveled when it is found, for example on the coast of Norway or Bikini Island in the Marshall Islands. Mary’s beans have been known to travel 15,000 miles by sea. Mary’s beans are used as good luck charms to ward off evil spirits and to ensure an easy delivery when held by a mother during childbirth.
Nickernuts are marble like seeds produced by a very spiny plant that has a very spiny pod containing two seeds. This spiny plant grows along the shores of many Caribbean islands and throughout tropical beaches of the world. In the Caribbean there are three common species of nickernuts, each with a different color seed: gray, yellow and yellow brown. The seeds are smooth and shiny and some seeds have latitudinal rings. When the seeds are mature the pod dries out and the nickernuts fall into the sand where they may sprout or be picked up by a wave and start an ocean journey. Nickernuts are used for the game of wari, a traditional African game that is played in many of the islands in the Caribbean.
There are many other sea beans and drift seeds that you can find on the beaches in the Caribbean.Â The sea coconut is the seed of a tropical palm called the sleeve palm, busso palm, or troolie palm which grows in the Caribbean and South America. The pretty oblong seed of the star nut palm polishes up nicely and is a unique find. A less desirable find are Manchineel, which can carry a chemical that is irritating and can cause a rash. Take the next opportunity to do a bit of beach combing and see what you can find.
Ocean currents, such as the Gulf Stream, transport seeds and beans from the tropics to distant shores. In a future issue we will learn more about ocean currents and ocean eddies.
Sea bean resources:
- Sea-Beans from the Tropics: A Collector’s Guide to Sea-Beans and Other Tropical Drift on Atlantic Shores, by Ed Perry, Ed & John V Dennis
- World Guide to Tropical Drift Seeds and Fruits by Charles R. Gunn, Pamela J Paradine & John V. Dennis
- Graines des Antilles by Servane Chauchix and Hector Poullet (In French).
Devi Sharp is a retired wildlife biologist. Currently she is exploring the Caribbean with her husband, Hunter, aboard their sailboat Arctic Tern.