A deciduous tree probably 30 ft and upwards high; young shoots often reddish and slightly hairy at first, becoming glabrous. Leaves of rather leathery texture, oval or obovate, tapered towards the base, more abruptly so towards the pointed apex, margins set with incurved teeth; 11⁄2 to 3 in. long, half as much wide; dull green and glabrous above; paler, downy in the vein-axils and usually hairy on the midrib beneath; stalk 1⁄8 to 1⁄2 in. long. Flowers solitary in the leaf-axils of the young shoots, cup-shaped, 2 to 21⁄2 in. wide, opening in June; flower-stalk 1⁄6 to 1⁄4 in. long, hairy. Bracts leaf-like, longer than the sepals. Petals five, creamy white, stained with red outside, scoop-shaped, 1 in. wide, the margins jagged. Stamens numerous, free, their stalks silky at the base; anthers yellow. Sepals five (occasionally six), ovate-oblong, 1⁄2 to 3⁄4 in. long, pointed, glabrous except for minute hairs on the margin; persisting to the fruiting stage and then much reflexed. Seed-vessel woody, ovoid, 3⁄4 in. long, quite glabrous, each of the five divisions tapered to a beak at the top. Seeds winged like those of an elm. Bot. Mag., t. 8771.
Native of S. Japan, with its main distribution in Kyushu and Shikoku. It was scarcely known in gardens until portrayed in the Botanical Magazine in 1918 from flowering specimens sent to Kew by Sir Edmund Loder in the previous year from his garden at Leonardslee, Sussex; it had also been in cultivation for some time at Nymans in the same county. Like all its kind, it is an attractive tree, and flowers freely. Its nearest allies are S. sinensis and S. monadelpha, in both of which, as in the present species, the bracts on the pedicels equal or exceed the sepals in length. But in those two species the ovaries and capsules are hairy, glabrous in S. serrata. S. sinensis is further distinguished by its unmistakeable bark, and S. monadelpha by its very small flowers and capsules.
This species received an Award of Merit when shown from Borde Hill, Sussex, in 1932.