Hibiscus arnottianus ssp. immaculatus, a member of the Malvaceae (mallow, hibiscus) family, is a tree up to 3 m (10 ft) tall with alternate, oval, toothed leaves measuring 5 to 7 cm (2 to 2.8 in) long and 4 to 6.5 cm (1.6 to 2.6 in) wide. Six lance-shaped bracts (leaf-like structures), 5 to 8 mm (0.2 to 0.3 in) long, are found under each of the faintly fragrant flowers, which are arranged singly near the ends of the branches. The calyx is 2.5 to 3 cm (1 to 1.2 in) long and cleft into five teeth with long, narrow points. The flaring petals are white and measure 8 to 11 cm (3.1 to 4.3 in) long and 2.5 to 3.5 cm (1 to 1.4 in) wide. Anthers, on spreading filament tips 1 to 2 cm (0.4 to 0.8 in) long, are arranged along the upper third of the white staminal column, which measures 10 to 14 cm (4 to 5.5 in) in length. Capsules are enclosed by the sepals and contain 4 mm (0.2 in) long seeds which are covered with yellowish-brown hair.