Description

Key Characters:

Growth Form: Trees to 15 m tall; bark gray or dark gray, smooth, deciduous.

Stems: Branchlets dark brown, sparsely yellow pubescent when young, glabrescent. Buds stipitate, with 2 glabrous, ribbed scales.

Roots:

Leaves: Leaves simple. Alternate. Blades obovate–lanceolate, obovate–oblong, ovate, or elliptic, 4–16 × 2.5–10 cm. Apex abrupt or acute, rarely acuminate. Base cuneate or broadly cuneate, rarely subrounded. Upper surfaces glabrous; lower surfaces with dense, resinous glands, yellow pubescent along veins, bearded in axils of lateral veins. Margins entire or remotely minutely serrate. Veins pinnate, lateral veins 8–16 on each side of midvein. Petioles robust, 1–2.5 cm, subglabrous. Stipules present.

Flowers: Flowers in female inflorescences numerous, in a panicle, ellipsoid, 2–2.2 cm × 7–8 mm; peduncle robust, 2–8 mm, glabrous; bracts ca. 4 mm, woody, persistent, base cuneate, apex rounded, 5-lobed. male inflorescence elongate, pendulous, cylindric, with numerous overlapping bracts, each bract subtending several bracteoles and 3 flowers; calyx 4-lobed; stamens (1–)4; anthers 2-loculed, thecae connate, apex glabrous. Flowers unisexual and plants monoecious. Calyx (sepals) 4-lobed in staminate plants; absent in pistillate plants. Corolla (petals) absent. Stamens 4. Ovary superior.

Fruit: Nutlets 2 in each bract axil; oblong; ca. 2 mm; compressed; with membranous wings ca. ½ as wide as nutlet. Seeds 1 per fruit; with straight embryo; without endosperm.

Ploidy: 2n = 28; 56

Habitat: Riverbanks or village margins; often forming pure stands.

Elevation Range: 200–2800 m.