The old crow's beak is a large climbing vine with thick grass or wood, which can reach 8 meters or more in length. Branches numerous, pubescent. Leaves opposite; The petiole is 2.5-6 cm long; Leaf blade papery, broadly ovate or triangular heart-shaped. Leaves opposite; The petiole is 2.5-6 cm long; Leaf blade is papery, broadly ovate, triangular, heart-shaped, 5- 10 cm long and 4-8 cm wide, with short tapering to acute tip, epicardium at the base, wavy to shallowly lobed edge, pubescent on both sides, and 3-7 palmate veins. Flowers are large, sometimes 2 peanuts are in leaf axils or drooping racemes; Pedicel about 5 cm long; Bracteoles 2, oblong-ovoid, 2.5-3 cm long, with short hairs; Calyx is annular and truncated; Corolla light blue, pale yellow or near white outside, 5-8 cm long, short corolla tube, swollen throat, nearly 5 equal parts of brim, and 7 cm in diameter; Stamens 4, 2 strong, old anthers hairy, anthers distant, short anthers hairless but only 1 anthers distant; Ovary slightly fleshy, 2 ovules per locule, stigma deeply 2-lobed, lobes and other large capsules pilose, about 3cm long, subglobose at the lower part, long beak at the upper part, like a crow's mouth when cracked. The seeds are hemispherical, and the surface is as dry as brain lines.