Tree to 25 m high, sometimes only a shrub; bark rough and fissured. Branches spreading but not pendulous. Shoots dark or brownish green, readily snapping with an audible crack when bent, not slender. Bud scales dark shining brown, becoming glabrous. Shoots and lvs somewhat silky when very young, but quickly glabrous. Petiole of lvs on reproductive shoots < 1 cm long. Lamina 5-15 × 1-2.5 cm, sometimes larger on water shoots, lanceolate, glaucous beneath, ± shining above, glandular-serrulate; apex acuminate. Stipules minute. Catkins usually ♂, rarely ♀, appearing with or after lvs. ♂ catkins 4-7.5 cm long, spreading or curving downwards, narrow-cylindric; rachis villous. Bracts 2-2.5 mm long, oblong-elliptic, incurved and ± cucullate when fresh, pale green or yellowish, densely clothed in antrorse hairs; apex rounded. Glands 2, 0.4-0.6 mm long, elliptic-oblong, rectangular to square. Stamens 2; filaments hairy towards base. ♀ catkins similar to ♂. Ovary glabrous, sessile or shortly stalked.