Perennial herb, 0·1–1·2 m. tall; underground stems vertical or nearly so, densely invested with thick white fleshy rounded scales c. 4 × 2–10 mm. after first year of growth, the new shoots scaly and arising from this region; plants strigulose with some glandular trichomes in the more densely pubescent inflorescence; stems with weakly marked elevated lines decurrent from the margins of the petioles. Leaves 2–5 × 0·4–2·5 cm., opposite near the base, alternate above, the margins and veins and sometimes the entire surface finely strigulose, narrowly ovate to narrowly lanceolate, mucronate to long-acuminate at the apex, rounded to obtuse or more rarely subcordate at the base, weakly or more often coarsely serrate with prominent forward-directed teeth, especially in the upper 1/2; petioles 1–2·5 mm. long, short but distinct. Inflorescence densely strigose with an admixture of glandular trichomes, erect in bud; flowers erect or somewhat drooping in bud. Floral tube 2–2·5 mm. across, 1·1–1·5 mm. deep, usually long-ciliate at the mouth with trichomes mostly 0·6–0·8 mm. long. Sepals 4·2–10 × 1·2–2·5 mm., narrowly oblong, acuminate or apiculate. Petals obovate, 6–16 × 3–10·5 mm., bright rose-purple, paler purplish, creamy or white, especially in smaller flowered forms, the notch c. the length of the petal. Anthers white, 17–3–2–5 × c. 0·8–1 mm.; filaments pale rose to white, those of the longer stamens 2·5–8 mm. long, of the shorter ones 1·5–5 mm.; pollen yellow. Styles 5–15 mm. long, pale rose to white, glabrous; stigma 4-lobed usually deeply so, white, the lobes 0·7–2 mm. long, papillose and receptive within, held far above the anthers in larger-flowered plants but reached by them in smaller-flowered ones. Capsules 3–9 cm. long, densely strigulose with an admixture of glandular trichomes, erect, on a pedicel 1–6 cm. long; seeds 1·3–1·6 mm. long, brown, the coma c. 5–7 mm., dingy white. Chromosome number n=18.
