Plant: Perennial forb .5-1 m, much branched, roots tuberous Leaves: Perennial forb .5-1 m, much branched, roots tuberous; leaves opposite, ovate-deltoid, 4-8 cm long Flowers: inflorescence terminal glomerate many-flowered cyme; flowers purplish-red, 3-6 cm long, tubular, opening in evening.