Glabrous perennial herb to 1 m tall, with slender rhizomes; stems erect, aerial, 2-lined, woody at base. Lvs sessile, 10-27 × 1-8 mm, lanceolate to oblong or ovate, with numerous pellucid and scattered intramarginal black glands; venation indistinct apart from main veins; base cuneate to subcordate; apex rounded, often mucronulate. Infl. terminal, a panicle of dense, many-flowered, corymbose cymes, more rarely cymes few-flowered; bracts similar to upper lvs. Sepals ± equal, 3-6 mm long, narrow-lanceolate to oblong, not accrescent, entire, acute to acuminate, sometimes with scattered black glands, sometimes the glands pellucid. Corolla 8-20 mm diam., golden, with scattered to numerous black marginal glands; petals obovate, much > sepals. Stamens in 3 bundles, < or = petals. Styles 3, = or > ovary. Capsule 6-8 mm long, narrow-ovoid, dry. Seeds 0.8-1.3 mm long, broad-cylindric, rugose.