Knicker Nut

''Guilandina bonduc'', commonly known as grey nicker, nicker bean, or knicker nut, is a species of flowering plant in the senna tribe, Caesalpinieae, that has a pantropical distribution. It is a liana that reaches a length of 6 m and scrambles over other vegetation. Stems are covered in curved spines. Its 2 cm grey seeds, known as nickernuts, are buoyant and durable enough to be dispersed by ocean currents.