Description from Flora of China
Acer tschonoskii Maximowicz subsp. koreanum A. E. Murray; A. tschonoskii var. rubripes Komarov.
Trees ca. 5 m tall, andromonoecious. Bark smooth. Branchlets very slender, glabrous; winter buds purple, ellipsoid, small. Leaves deciduous; petiole purple, 5-7 cm; leaf blade abaxially pale green, triangular-ovate, 6-10 × 6-8 cm, papery, abaxially rufous pubescent at vein axils, adaxially glabrous, primary veins 5, base cordate or subcordate, doubly serrulate and lobulate with dense obtuse teeth, 5-lobed, rarely 3-lobed; middle lobe ovate, apex acuminate; lateral lobes triangular-ovate; basal lobes ovate, apex obtuse. Inflorescence terminal on leafy branchlets, racemose, 5-7(-10)-flowered. Pedicel 7-10 mm, slender, glabrous. Sepals 5, ovate-oblong. Petals 5, obovate- oblong, slightly longer than sepals. Stamens 8, glabrous, very short in pistillate flowers. Disk glabrous, flat, intrastaminal. Ovary reddish, purple when young. Nutlets flat, smooth, ca. 8 × 5 mm; wing including nutlet 2-2.5 × 1-1.2 cm, wings spreading obtusely. Fl. May, fr. Sep.
The typical subspecies occurs in Japan.
One of us (Chang) believes that this taxon should be Acer komarovii Pojarkova and is different from A. tschonoskii (of Japan) by the number of flowers per inflorescence (5-7 flowers vs. 9-20 flowers).
Mixed alpine forests; 300-1200 m. Jilin, Liaoning [N Korea, E Russia].