Erect shrub, 2-5 m tall, non-sprouting. Branchlets sparsely to moderately tomentose at flowering. Leaves narrowly linear, flat or trigonous, twisted through 90° at base, 3-18 cm long, 1.5-4 mm wide, glabrous; marginal veins prominent; longitudinal veins prominent, 1-3 above and below; secondary veins obscure. Inflorescence a solitary axillary umbelliform raceme, with 6-18 flowers; pedicels cream-white, glabrous. Perianth cream-white. Pistil 4-6 mm long; gland a small flap, 0.2-0.3 mm high. Fruit shortly stalked, ovate or obliquely ovate, 1.6-2.5 cm long, 8-11 mm wide, shortly beaked, shortly apiculate. Seed obliquely narrowly obovate-elliptic, 10-16 mm long, 3.5-6 mm wide; wing extending partly down both sides of body, more broadly on adaxial side, blackish brown.