Herbs perennial, (15--)25--40(--50) cm tall. Roots vertical, gray-brown, robust, lignified; root crowns multibranched, slightly lignified, with procumbent stems. Stems sparsely caespitose, erect, pale yellowish green, ± black at apex, simple, basally glabrous, apically hirtellous with intermixed black glandular hairs. Basal leaves oblanceolate or linear-oblanceolate, 4--10 cm × 6--10 mm, base attenuate into petiole, apex obtuse or acute; cauline leaves 1--4 pairs, narrowly elliptic, smaller than basal leaves, nearly sessile, slightly sheathed, both surfaces glabrous, ciliate, hairy at veins abaxially, midvein prominent; distal leaves narrowly lanceolate, sometimes withered, coarsely glandular hairy. Flowers solitary, sometimes 2 or 3, nutant, erect in late anthesis. Pedicel subequaling calyx, elongating in late anthesis, viscid, villous. Calyx globose-campanulate, saccate, 1.8--2.2 × 1.2--1.5 cm, membranous, sparsely robust glandular hairy, contracted at apex, opened in late anthesis; veins dark violet, with brown-violet glandular hairs, coherent at calyx teeth; calyx teeth triangular, margin ciliate, apex acute. Androgynophore 2--3 mm, villous. Petals exserted 1--3 mm beyond calyx, dark violet; claws 1.4--1.6 cm, cuneate, with narrow auricles, limbs emarginate or shallowly bifid; lobes entire or shallowly toothed, rarely 1-toothed obscurely at base of two sides; coronal scales small, cuneate, with minute teeth at apex. Stamens included. Styles 5. Capsule orbicular, 1.2--1.5 × 1--1.4 cm, 5-toothed. Seeds dark brown, reniform, ca. 1.4 mm, thick, flat, with prominent papillae abaxially. Fl. Jun--Jul.
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