Perennial herb (5)-20-100 cm tall, often much-branched, in autumn producing short ± horizontal stolons from base of plant; stolons terminating in fleshy or leafy buds below or above ground; flowering stems erect; plants covered with erect or appressed eglandular hairs. Lvs opposite below, alternate in the infl., dark green, strigillose, especially along the veins and margins, 3-8 × 1.5-3.4 cm, irregularly serrate, narrowly-ovate or ovate; apex acuminate or acute; base broadly cuneate to truncate; petiole 1-6 mm long. Infl. nodding, with glandular hairs and strigillose. Fls erect. Ovary 2-3 cm long. Floral tube 1.2-2 mm deep, with a conspicuous ring of long hairs inside. Sepals keeled, 5-6.5 × 1.2-1.7 mm. Petals rose-purple, 7.5-10 × 4-5.5 mm. Filaments of the longer stamens 3.5-5.5 mm long. Style 3.5-5.5 mm long, rosy purple or white, glabrous or nearly so; stigma deeply 4-lobed, the lobes 1.2-1.8 mm long. Capsule 4-8 cm long; fruiting pedicel 0.8-1.5 cm long. Seeds 1-1.2 × 0.45-0.55 mm, obovoid, coarsely papillose.