Shrubs to 1 m tall. Stems obtusely 4-sided, nodes slightly inflated; branchlets 4-sided, densely denticulate, glabrous. Petiole 1-7.5 cm, densely bullate; leaf blade stiffly oblong-lanceolate, elliptic, or obovate, 10-17(-20) × 3-7(-8) cm, papery, surfaces glabrous and densely bullate, secondary veins 2 on each side of midvein, base cuneate to broadly cuneate, margin entire, apex acuminate to acute. Inflorescences terminal, cymose contracted to umbellate. Pedicel 0.8-1.8 cm, densely bullate. Hypanthium funnel-shaped, ca. 6 mm, 4-sided, densely bullate, glabrous or with dense twisted setose trichomes. Calyx lobes long triangular, ca. 6.5 mm, apex acuminate to obtuse. Petals ca. 1.4 × 0.8 cm. Stamens equal; filaments filiform, ca. 7 mm; anthers lanceolate, ca. 1 cm; connective decurrent, forming a shout spur, abaxially tuberculate. Ovary ovoid, apical margin with glandular trichomes. Capsule cup-shaped, ca. 7 × 6 mm, 4-sided; hypanthium exceeding capsule, 8-ribbed. Fl. May-Jul, fr. Jun.
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