Perennial herb (0.17-)0.3-0.55 m tall, erect or sometimes ascending from creeping and rooting base, with stems few to numerous, simple or usually branched below inflorescence or throughout. Stems incompletely 4-lined or 2-lined when young, nearly always soon becoming terete; internodes 25-80 mm, shorter than leaves except upper (slightly longer) or rarely all longer. Leaves sessile; lamina 20-65(-80) ´ 10-32 mm, broadly oblong or oblong-ovate to narrowly oblong or oblong-lanceolate (reducing in size down stem), rather paler beneath, not glaucous, plane, chartaceous; apex rounded to shallowly retuse, margin entire, base cordate-amplexicaul; venation: 4-6 pairs of main laterals from lower half of midrib, with subsidiary midrib branches and densely reticulate tertiary venation not or scarcely prominent beneath; laminar glands pale, dense, unequal dots or short streaks; intramarginal glands pale, dense, small. Inflorescence 1-7-flowered from 1-3 nodes, corymbiform, sometimes with flowering branches from up to 5 nodes below, the whole then narrowly pyramidal to cylindric; pedicels 12-22 mm (-45 mm in fruit); bracts and bracteoles foliose, ovate, persistent. Flowers 20-40 mm in diam., stellate; buds narrowly ovoid to cylindric, obtuse to rounded. Sepals 8-10 ´ 2-4 mm, sometimes enlarging up to 15 ´ 6.5(-8) mm in fruit, free or basally united, ± imbricate, subequal or unequal or rarely foliaceous, erect in bud, spreading to deflexed in fruit, narrowly or broadly oblong or elliptic to lanceolate or ovate-lanceolate or triangular-lanceolate, rounded to obtuse or rarely shortly mucronate, entire but margin undulate; veins (5)7-9, branching distally and reticulating, midrib scarcely differentiated; laminar glands rather sparse, ± punctiform, distal and submarginal, also a few basal, linear; marginal glands dense, small. Petals bright yellow, not tinged red in bud, 12-18 ´ 4-8 mm, 1.5-1.8 ´ sepals, oblong-oblanceolate, slightly curved, rounded, without apiculus, margin entire; laminar glands pale, linear, sometimes interrupted distally; marginal glands absent. Stamen fascicles 5, each with 15-30 stamens, longest 10-24 mm, c. 0.85-1 ´ petals; anther gland amber. Ovary 5(6)-locular, 4-9 ´ 4-6 mm, ovoid; styles 5(6), 4.5-13 mm, 1-1.8 ´ ovary, 0.5-0.9 united or appressed (when short); stigmas narrowly capitate. Capsule 14-21 ´ (5)7-14 mm, broadly to narrowly ovoid or subcylindric, 1-2.1 ´ sepals, obtuse, with numerous narrow longitudinal vittae. Seeds dark reddish-brown to greyish-brown, 1.3-1.5 mm, cylindric, not curved, shallowly carinate, without terminal expansion; testa densely shallowly linear-reticulate.