Woody or herbaceous twiners. Leaves
petiolate, ovate or orbicular, cordate base, entire, lower surface minute black
dots. Flowers axillary cymes, bracts small, caducous. Sepals equal or unequal,
ovate, elliptic, obtuse or emarginate, enlarged. Corolla funnel-shaped, red or
purple. Stamens and styles included. Ovary 4-celled, 1 ovule in each, style 1,
filiform, stigma bi-globular. Fruits enclosed in enlarged calyx, dehiscing with
4 openings. Seeds 4, pubescent.