An evergreen shrub up to 15 ft high in the wild, with a rough bark; young shoots covered with pale yellow, glistening scales. Leaves aromatic, oval, sometimes slightly obovate or ovate, 11⁄2 to 3 in. long, 5⁄8 to 11⁄4 in. wide, scattered along the shoot, pointed, rounded or slightly heart-shaped at the base, dark green and somewhat scaly above, downy along the midrib, paler and much more scaly beneath, the scales large, some yellowish brown, others dark brown or black; stalk 1⁄4 to 5⁄8 in. long. Flowers produced in April or May in terminal trusses of five to six. Calyx minute, scaly. Corolla pale yellow with yellow-green spots on the upper lobes, about 2 in. wide, broadly funnel-shaped, slightly scaly outside. Stamens ten, whitish, hairy near the base. Ovary scaly; style glabrous. Bot. Mag., t. 8400. (s. and ss. Triflorum)
R. ambiguum is abundant in W. Szechwan, China, whence it was introduced by Wilson in 1904. It is a species of little ornamental value, allied to the Himalayan R. triflorum, but in that species the leaves are glabrous on the midrib above, and the scales on the underside are very small, widely spaced (more than their own diameter apart) and equally coloured (Davidian, R.C.Y.B. 1963, pp. 172, 174).