Hibiscus clayi, a member of the Malvaceae (mallow, hibiscus) family, is a perennial shrub or small tree 4 to 8 m (13 to 26 ft) tall with stems bearing sparse hairs at the branch tips. The oval or elliptical leaves are usually 3 to 7 cm (1 to 3 in) long and 15 to 35 mm (0.6 to 1.4 in) wide and have a hairless upper surface and slightly hairy lower surface. The leaf margins are entire or toothed toward the apex. The flowers are borne singly near the ends of the branches. The flaring petals are dark red, 45 to 60 mm (1.8 to 2.4 in) long, and 10 to 18 mm (0.4 to 0.7 in) wide. The green tubular or urn-shaped calyx is 15 to 25 mm (0.6 to 1.0 in) long with five or six shorter bracts beneath. The fruits are pale brown capsules 12 to 14 mm (0.5 to 0.6 in) long, containing about 10 oval, brownish black seeds 4 mm (0.2 in) long.