I just finished a seed necklace design that I can only ever make about once every three years when I have collected enough of the seeds from beaches for one. At times like these I try not to ponder the economic logic of my practice! I collect various hard shelled bouyant seeds that have arrived on the ocean currents. They bob in on the plastic and pumice flotsam tide and are quite rare on beaches near me. The smaller bean seeds are more plentiful and actually grow in the headlands behind the beaches.
After watching The Wrecking Season about flotsam and jetsam along the Atlantic Cornish coast (recommended by Rebecca Crawford), I realised that these same tropical seeds wash up on beaches all over the world - they are longshore drifters of the bean kingdom and even have their own fan clubs with a great Sea Bean website and a symposium every year on the topic of sea beans.Now some of the beans I am finding in QLD are probably from Far North QLD - where they are called Burney Beans, Mucuna gigantea - you can rub them on stone or together until they are very hot and burn people. A useful bean indeed. And the larger matchbox bean is also one I find alot, sometimes encrusted in coral. But others like the nickernuts Caesalpinia bonduc sometimes called sea pearls, may come from further afield and have had many past uses including as currency in South America.
There is some frightening sea bean craft out there so be warned but I discovered some exquisite sea bean jewels in the Kew Garden Economic Botany Collection.