Seeds of Vigna marina (Burm.) Merrill survive up to 25 years flotation in salt water

Vigna marina (Burm.) Merrill is a pan-tropical legume found in littoral zone vegetation in north-eastern Australia and nearby islands. Its seeds are buoyant and ocean currents are the presumed main mechanism for its dispersal. In 1985, we immersed seeds in salt water to see how long they would remain buoyant and viable. In 2010, we germinated and grew plants from some of the last of these seeds. We concluded that given reasonably favourable conditions the potential exists for viable seeds to be dispersed over vast distances on ocean currents.