Herbs, 50-80 cm tall, glabrous throughout. Rhizome creeping, short, stout, nodose. Leaves basal and cauline, trifoliolate; cauline leaves opposite; leaflets abaxially pale green, adaxially dark green, ovate, 7.5-15 × 3.5-9 cm, leathery, abaxially with conspicuously raised veins, base of terminal leaflet truncate or obtuse, base of lateral leaflets oblique but not cordate, margin remotely spinose-serrate, apex acute or acuminate. Flowering stem with 2(or 3) trifoliolate opposite leaves. Panicle many (ca. 50) flowered, ca. 28 × 7 cm. Pedicel 7-15 mm, slender. Flowers ca. 4 mm in diam. Outer sepals 4, outer pair purple, suborbicular, ca. 2 mm, inner pair white, ca. 2.5 mm; inner sepals 4, lanceolate, ca. 2 mm. Petals 4, suborbicular, ca. 1 mm, base broadly cuneate, without spur, apex slightly involute. Stamens ca. 2.2 mm; filaments flat, ca. 0.7 mm; anthers ca. 1.5 mm, valved, apex of anther connective obtuse. Pistil ca. 2.2 mm; style ca. 1 mm. Capsules ca. 1.5 cm; style rostriform, ca. 5 mm. Fl. Apr-May, fr. May-Jun.