Herbs to 2 m tall, anisophyllous. Stems subterete to 4-angled, sulcate, pubescent with brownish trichomes or glabrescent. Leaves petiolate but apicalmost ones subsessile; petiole 0.5-4 cm, flat, slightly winged, pubescent or glabrous; leaf blade ovate, elliptic, or ovate-lanceolate, 4-20 × 1.5-7.5 cm, smaller of pair ca. 1/2 size of larger one, both surfaces pilose to subglabrous and with cystoliths, abaxially pale green, adaxially green, secondary veins 7-11 on each side of midvein, base cuneate and decurrent onto petiole, margin crenate-serrate, apex acuminate. Inflorescences capitate, 4-8-flowered, enveloped by bracts; peduncle short, usually simple; outer sterile bracts sessile, ovate, ovate-oblong, or oblong-ovate, 3-5 × 2-2.5 cm, equal or unequal, persistent, margin dentate, apex obtuse, rounded, or fimbriate; inner bracts fertile, obovate to spatulate, 2-3 × 0.7-0.8 cm, margin ciliate; bracteoles linear to oblanceolate, 13-23 × 1.5-3 mm, pubescent or glabrous, margin entire or sometimes dentate or fimbriate toward apex, apex acuminate. Calyx 1.5-2 cm, pubescent, 5-lobed almost to base; lobes linear, 12-19 × 1-2 mm, subequal, outside apically pubescent. Corolla violet, 4.5-5.5 cm, outside glabrous, inside glabrous except for trichomes retaining style; tube basally cylindric and ca. 2 mm wide for ca. 1.5 mm then ventricose and widened to ca. 1.5 cm at mouth; lobes ovate, 8-9 × 8-10 mm, apex rounded. Fertile stamens 4, included; shorter filament pair 3-5 mm, glabrous; longer filament pair 5-7 mm, pilose; anther thecae oblong, 2-3 × ca. 2 mm, apex apiculate; connective excurrent; staminode occasionally present, small or inconspicuous; pollen type 3. Ovary glabrous; style ca. 2.5 cm, hirsute. Capsule fusiform, 1.2-1.8 cm, glabrous, 4-seeded. Seeds brown, ovate in outline, 3-5 × 2.5-4 mm, pilose; areola small. Fl. May-Sep.
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