Small, deciduous to sometimes evergreen tree. Bark grey to brown, rough and flaking in to squares lower on older trunks, grey and smooth higher up and on younger trees; branches corky and with swollen nodes and conspicuous lenticels. Leaves opposite, 3-veined from (near) the base, narrowly elliptic, 3-8 cm long, rigid or leathery, hairless with a hard, spiny apical point; margin entire; petiole thick, up to 4 mm long. Inflorescences in tight, axillary clusters, c. 2 cm wide; flowers greenish-white, up to 9 mm long. Fruit up to 12 cm in diameter, with a hard, woody shell, bluish-green, yellow when ripe, edible but less tasty than of other species.