| HABIT: It is a greenish or pale to dark colored perennial climber with woody stem. |
| ROOT: Tap root, long, cylindrical, branched, irregularly bent, about 3 to10 mm in diameter, grayish-brownish externally, smooth, finely wrinkled, inner surface white, fracture short and splintery, taste strongly bitter, odor characteristic. |
| STEM: Twining, slender, woody at the base, grooved, glabrous, brownish externally, smooth, finely wrinkled, inner surface white, fracture short and splintery, taste strongly bitter, odor characteristic. |
| LEAVES: Simple, alternate, linear-oblong to obovate oblong or subpanduriform, obtusely acuminate, entire with somewhat undulate margin, glabrous, cuneate at base, rounded, sub-truncate or subcordate, 3.5 to 12.5 cm long and 1.5 to 7.5 cm broad, taste bitter, odor characteristic. |
| FLOWER: In few flowered axillary racemes, bracts small, ovate, acuminate, opposite to the pedicels, pedicel long, thickened above, perianth greenish white, up to 4.5 cm long with globose inflated base, bent at right angle and suddenly narrowed into a cylindrical tube with oblique trumpet-shaped mouth gradually passing into a long narrow, linear-oblong, obtuse brownish lip. Anthers 6, style 6-lobed. |
| FRUIT: A capsule, 4 to 5 cm long, oblong or globose-oblong opening from below upwards, 6 valved, the pedicel split into 6 filaments. |
| SEED: Deltoid, ovate, acute, flat, winged |
