An evergreen shrub or small tree, sometimes 30 ft high in the wild; young shoots stout, often 5⁄8 in. in diameter, scurfy white when young, becoming yellowish. Leaves oblanceolate to obovate, abruptly narrowed at the apex to a short point, tapered at the base to a thick, winged, yellowish stalk that is up to 1 in. long and 1⁄2 in. wide, 6 to 9 in. long, 2 to 4 in. wide, dark dull green and glabrous above, covered beneath with a pale, very close scurf; midrib broad and yellow above. Flowers produced from February to April in trusses of twelve to eighteen blooms and about 6 in. wide. Calyx small, 1⁄12 in. long, with even triangular teeth; flower-stalks 1 to 11⁄2 in. long, thinly downy. Corolla bell-shaped, 2 in. wide, nearly as deep, seven-lobed, white with a small purple blotch at the base. Stamens fourteen, shorter than the corolla, their white stalks downy towards the base. Ovary and style glabrous. (s. Grande)
Native of W. Szechwan; discovered by Wilson in 1904 and introduced by him. It is a little-known species, rare in cultivation, which is placed in the Grande series, of which it is an aberrant member, differing from all the other species, except R. peregrinum, in its glabrous ovary; the petiole is very short, with the decurrent base of the blade forming a wing on either side, as in R. praestans. During his second expedition for the Arnold Arboretum Wilson collected seed from trees 25 to 30 ft high, with trunks 2 to 21⁄2 ft in girth.
R. peregrinum Tagg – Near to R. watsonii, but with the leaves rounded to subcordate at the base and the petiole up to 1 in. long. It occurred as a rogue among plants of R. galactinum raised by E. J. P. Magor of Lamellen, Cornwall, from Wilson’s 4254, collected in W. Szechwan on the Panlanshan, during his second expedition for the Arnold Arboretum.