Herbs, annual, robust, from loose basal rosette. Stems branched from base (proximal branches longer), 5–20 dm, viscid-pubescent. Rosette leaves: petiole length equaling blade; blade ovate or orbiculate, 6–12 cm, surfaces viscid-pubescent, somewhat scabrous adaxially. Cauline leaves: petiole length 1/3–1/6 blade; blade elliptic to lanceolate, becoming very narrow near inflorescence, 10–25 cm, apex acuminate, surfaces viscid-pubescent, somewhat scabrous adaxially. Inflorescences few-branched, somewhat leafy; flowering crepuscular. Pedicels 0.5–2 cm. Flowers: calyx strongly purple-veined, 1–2 cm, membranous, viscid-pubescent (hairs without swollen bases), lobes long-triangular, unequal, longest equaling tube; corolla straight, 2.5–10 cm (excluding limb), viscid-puberulent externally, tube white or white tinged with greenish purple, sometimes striped, 0.8–4 cm × 2–3 mm, widening to throat 1–4 × 5 mm, glabrous or minutely puberulent internally, limb spreading, white, circular, 2–4 cm diam., lobes shallow, deltate or emarginate; stamens inserted near base of throat, included; filaments unequal, in 2 equal or unequal pairs, 4 cm, 1 filament shorter than either pair, pubescent proximally; style straight, just surpassing longest stamen pair. Capsules broadly ovoid, 1–1.2 cm. Fruiting calyces tearing along membranous sinuses, covering ca. 1/2 of mature capsule. Seeds 0.9–1 mm. 2n = 24.