Perennial. Stems erect, up to 1 m tall, glabrous, striated. Leaves large, up to 12 x 7 cm, broadly lanceolate to oval or ovate, upper sessile, lower petiolate, lower surface hirsute on the veins, upper almost glabrous; margin dentate to serrate. Flowers large, usually 1, sometimes more, in the axils of upper leaves forming a raceme. Calyx teeth linear, c. 1 cm long, margin ciliate. Corolla campanulate, 2 to 4 cm, dark purple-blue, lobes acute. Filaments broad at the base, hairy. Style included with 3 linear stigmas. Capsule c. 1 cm long, dehiscing at the base.