Japan Flora: Shrub with spreading to as cending branches, the branches terete, grayish brown, glabrous; leaves trifoliolate, on petioles 2-3 cm. long, the lateral leaflets sessile, ovate or ovate-elliptic, 3-7 cm. long, 1.5-3 cm. wide, acuminate, acute or acuminate at base, mucronate-serrate, the terminal one attenuate on a petiolelike base, paler and glabrous (var. glabra. Nakai) or pubescent on midrib beneath; inflorescence a racemelike panicle, terminal on young branchlets, 5-8 cm. long; flowers white, the pedicels 8-12 mm. long; calyx-segments linear-oblong or oblanceolate, obtuse, erect, 7-8 mm. long3 greenish white; petals simulating the sepals and as long, white; capsules slightly inflated, short-stiped, shallowly and broadly 2-fid, 2-2.5 cm. wide, the stigma at first connate; seeds lustrous, pale yellow, obovoid, about 5 mm. long. May-June. Woods in lowlands and hills;

Hokkaido, Honshu, Shikoku, Kyushu; common. Korea, Manchuria, and China.

Korea Flora: Deciduous shrub or small tree. Height 3-5m. Winter buds and young shoots: Semicircular or triangular, with sharp tips, 3-4mm long, 2 bud scales. Two pseudo-terminal buds clustered together, larger than lateral buds. Branches round, grayish-green, young branches glabrous. Leaf scars semicircular or triangular. Leaves opposite, trifoliate. Leaflets sessile, middle leaflet with base extending into a petiolule. Leaflets ovate or ovate-elliptical, narrowed at both ends. Upper surface glabrous, lower surface with hairs on veins. Leaflet size (3)4-10cm × (1)1.8-3.5(4)cm, margins with needle-like fine serrations. Petiole 2-3cm long. Flowers in terminal panicles 5-8cm long. Peduncle 8-12cm long, pedicels 1.0-1.2cm long. 5 white sepals, 5 petals, and 5 stamens. Single pistil divided into 2 at the top, each with one style. Fruit and seed: Capsule inflated like a rubber pillow, semicircular, split into 2 at the top, 1.5-2.5cm long, apex acuminate. 2-chambered ovary with 1-2 seeds in each chamber. Seeds spoon-shaped, yellow, glossy, 5mm long.

Flowering: Late April to mid-June

Fruiting: Late August to mid-October

Distribution: Northeastern to central China, Hokkaido to Kyushu in Japan; throughout Korea

Ecological characteristics: Intermediate between shade-intolerant and shade-tolerant, grows well in moist soil.