Herbs 50-100 cm tall, weakly anisophyllous. Stems 4-angled, pubescent, glabrescent, fragrant when dry. Petiole to 2 cm, pubescent; leaf blade broadly oblong-elliptic, to 18.5 × 6 cm, both surfaces sparsely pubescent especially on veins, adaxially with prominent cystoliths, secondary veins 4-7 on each side of midvein, base cuneate and decurrent onto petiole, margin crenate, apex acute. Inflorescences terminal, simple spikes, 3-11 cm, sometimes with branches arising in apical leaf axils; rachis pubescent with gland-tipped trichomes; bracts linear-spatulate, 10-12 × 2-2.5 mm, sparsely pubescent and gland-tipped pubescent, densely covered with white cystoliths, 1-veined; bracteoles linear, ca. 5 × 1 mm, pubescent, abaxially densely covered with cystoliths. Calyx 5-lobed to base; lobes linear, 8-9 × ca. 1 mm, subequal, pubescent, outside covered with prominent cystoliths. Corolla pink to pure white, ca. 3.2 cm, straight, outside glabrous, inside glabrous except for trichomes retaining style; tube basally cylindric and ca. 2 mm wide for ca. 1 cm then gradually widened to ca. 1 cm at mouth; lobes orbicular, ca. 5 mm in diam. Stamens 4, included; shorter filament pair ca. 4 mm, glabrous; longer filament pair ca. 7 mm, puberulent; anther thecae oblong, ca. 3 mm; pollen type 4. Ovary obovoid, ca. 3 mm, gland-tipped pilose at tip; style ca. 1.5 cm, glabrous. Capsule narrowly oblong-obovoid, 8-10 × ca. 2.5 mm, gland-tipped pilose, 4-seeded, apex apiculate. Seeds ovate in outline, ca. 2 × 2 mm, pubescent; areola small, glabrous. Fl. Apr-Jun, Dec, fr. Jun-Jul.
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