An evergreen shrub or small tree up to 30 ft high; young shoots clothed with red-brown, soft felt. Leaves oval or obovate, rounded at the apex, less so or broadly tapered at the base, 6 to 13 in. long, about half as much wide, dark green and ultimately glabrous above, covered beneath with a rich red-brown down; stalk very stout, flattened above, up to 11⁄4 in. long. Flowers opening in April, numerously and closely packed in a truss 5 in. or more wide. Calyx a mere wavy rim; flower-stalks 1 to 11⁄3 in. long, downy. Corolla broadly and obliquely bell-shaped, eight-lobed, 11⁄2 in. wide, pale yellow flushed with rose and blotched with crimson at the base. Stamens sixteen, nearly or quite glabrous. Ovary densely clothed with down; style glabrous. (s. Falconeri)
Native of N.W. Yunnan and bordering parts of upper Burma, but of limited distribution; discovered by Forrest in 1910 on the Shweli-Salween divide and introduced by him in 1912. His F.24139 is also from this area and a plant raised from it received an Award of Merit when shown by Col. The Lord Digby, Minterne Abbey, Dorset, in 1956. It is also in cultivation from Farrer 873 (Hpimaw pass, Nmai-Salween divide) and Rock 03904. It occurs at altitudes of up to 11,000 ft.
R. basilicum is perfectly hardy south of London in light woodland.