Betula luminifera Winkler

A tall tree, the younger branches bright reddish brown; young twigs covered more or less densely with pale hairs or down. Leaves ovate, 21⁄2 to 5 in. long, 11⁄2 to 31⁄2 in. wide, rounded or slightly heart-shaped at the base, pointed, unequally toothed, each tooth ending in an abrupt, slender point, ciliate, downy on both surfaces, dark dull green above, bright green beneath, covered with minute, lustrous resin-glands; veins nine to twelve; leaf-stalk 1⁄2 to 3⁄4 in. long, downy or nearly glabrous, reddish. The young, expanding leaves are of a pretty, red tinge. Fruiting catkins 11⁄2 to 31⁄2 in. long, cylindrical, 1⁄4 in. diameter, borne singly; scales very small, the middle lobe several times larger than the side ones. Wings of fruit about as broad as the nutlet.

This species is closely allied to the Himalayan B. alnoides (see below), but is a native of W. China; discovered by the French missionary Farges in E. Szechwan and introduced by Wilson in 1901 and again in 1907. According to Wilson it is the common low-level birch in Szechwan and Hupeh, found up to an altitude of about 8,000 ft and rarely more than 65 ft in height. Trees at Kew grew well and were curiously distinct in the resinous sheen beneath the leaves, which became more apparent as the leaf dried. They varied considerably in the downiness of the young shoots. The last of these died in 1960 when 46 ft high.