Polyscias lydgatei, a member of the Araliaceae (ginseng) family, is a tree 23 to 33 ft (7 to 10 m) tall. Leaves are glabrous, 34 to 40 (50) cm (13 to 16 (20) in) long, leaflets are (7) 9-11, broadly elliptic or ovate to oblong-elliptic, lateral leaves often slightly sickle-shaped, 7 to 9 cm (2.8 to 3.5 in) long, 3 to 3.5 cm (1.2 to 1.4 in) wide, with lower pair often smaller. Yellow to yellow-green flowers are erect in a twice compound umbel (unbranched inflorescence with a very short axis), each with a terminal spherical umbellule (secondary umbel) of 26 to 47. Stamens are 12 to 18, two to three times as many as petals, in a single whorl and the ovary is fully inferior. Fruit are 1 cm (0.4 in) long, 0.5 to 0.7 cm (0.2 to 0.3 in) wide, globose to ovoid with a small 1 mm (0.04 in) beak. Seeds are globose and 4 to 5 mm (0.15 to 0.2 in) long.