Vines, climbing to tops of trees; rhizomes slender, branched. Leaves: petioles to 28 cm. Leaf blade 10-25 × 10-29 cm, membranous; venation 5 or 7. Inflorescences to 32 cm; rachis puberulent, glandular. Flowers: sepals 1.6-4.6 × 0.6-2 mm, glabrous. Staminate flowers: stamens to 3 mm. Pistillate flowers: ovary to 2 mm. Drupes green at maturity, darkening to deeper green or black upon drying, 15-25 × 10-20 mm.
Phenology: Flowering spring–summer.
Habitat: Primarily along rivers or smaller streams in deciduous forests
Elevation: 0-350 m
Ala., Ark., Fla., Ga., Ill., Ind., Kans., Ky., La., Miss., Mo., Okla., S.C., Tenn.
Calycocarpum lyonii has been reported as occurring in Texas, but no Texas specimens have been seen.