The double butterfly is a perennial herbaceous vine. Leaves opposite, entire, ternate veins, basal leaves obovate, 4-6 centimeters long, 2-2.5 centimeters wide, sessile; stem leaves ovate-orbicular or ovate-acicular, 4-8 centimeters long, 1.5-3.5 centimeters wide, acuminate at the tip, rounded or slightly cordate at the base. Flowers solitary in leaf axils or several in cymes, petiole ca. 3 mm; calyx tubular, tube 1-1.5 cm, 5-lobed, lobes linear, 0.5-1 cm; corolla white or blue, with purple stripes, apical 5 lobes, lobes triangular, ca. 5 mm, with pleats between lobes; stamens 5, inserted on corolla tube, style ca. 5 mm, stigma dilated. Stamens 5, inserted on corolla tube, style ca. 5 mm, stigma dilated, 2-lobed. Capsule 2-lobed; seeds many, trigonous, winged on the ribs, the wing on one of the ribs narrower than on the other two.