These odd shaped angular corky nuts are a very common drift seed on the beaches of Borneo. The nuts have frequently been gnawed by rats to get at the seed inside. These nuts originate from two very similar mangrove trees with very large fruits. This article concerns Xylocarpus granatum which has the largest fruit. See also our article on Xylocarpus moluccensis. The nuts of both species are the same size and impossible to tell apart.