Tree 12-35 m high, lacking buttresses. Leaf with petiole 0.3-4.5 cm long, and blade subcoriaceous to coriaceous, 7.5-23+ (leaf broken) by 3.8-13.5 cm, usually elliptic to broadly elliptic, occasionally narrowly elliptic or ovate, the base obtuse, rounded, slightly cordate, truncate or cuneate especially in narrow leaves and the apex broadly acute, obtuse, rounded, apiculate or sometimes acute, especially in narrow leaves; Stipules triangular-ovate to ligulate, 0.5-1.3 by 0.4-0.5 cm, caducous, abaxial surface tomentose or sparsely pubescent. Inflorescence either false-terminal or terminal; Flowers bisexual and male, 5-8 mm diameter; 5-6-merous (except gynoecium); Fruits ellipsoid or irregularly globose-oblate, up to 2.5-5 cm long by 2.5-5.8 cm diameter;
This is a rather variable and perhaps heterogeneous species with large fruits, probably closely related to S. versteeghii, which has much denser indumentum on the inflorescence. A distinctive population with terminal, rather than false-terminal inflorescences and rather bullate leaves () occurs on Mt Giluwe and the Schrader Range at 2000-2500 m, and another variant has some floccose indumentum on the leaves.