Sophora japonicus (primitive species), tree, 25 meters high; bark gray-brown with longitudinal cracks. The branches were green and hairless. The pinnate compound leaves are 25 cm long; the leaf shafts are initially sparsely pilose and immediately shed; the base of the petiole is enlarged and envelops the buds; the shape of the stipules is changeable, sometimes ovate, leaf-shaped, sometimes linear or diamond-shaped, Fallen; leaflets 4-7 pairs, opposite or nearly alternate, papery, ovate-lanceolate or ovate-oblong, 2.5-6 cm long, 1.5-3 cm wide, apex acuminate, small pointed, The base is broadly wedge-shaped or nearly round, slightly slanted, the underside is off-white, initially sparsely pubescent, and revolving glabrous; 2 small stipules, subulate.

The panicle is terminal, often pyramid-shaped, up to 30 cm long; the pedicel is shorter than the calyx; 2 bracteoles, shaped like small stipules; the calyx is shallowly campanulate, about 4 mm long, and the calyx teeth are 5, nearly as large, round Shaped or obtuse triangle, gray-white pubescent, calyx tube nearly glabrous; corolla white or light yellow, flag petals nearly round, length and width about 11 mm, short stalk, purple veining, apex slightly absent, base Shallow heart-shaped, wing petals oval-oblong, 10 mm long, 4 mm wide, apex rounded, base oblique halberd, no wrinkles, keel petals are broad ovate-oblong, equal length to wing petals, width up to 6 Mm; stamens nearly separated, persistent; ovary nearly glabrous.