Herbs, 30-70 cm tall, sometimes to 80 cm tall. Rhizome creeping, stout, 2-8 mm in diam. Leaves basal and cauline, trifoliolate; leaflets adaxially dark green, narrowly ovate, 4-15 × 1.3-7 cm, leathery, abaxially glaucous, glabrous or sparsely pilose, adaxially glabrous, both surfaces with conspicuous reticulate veins, base deeply cordate with usually rounded lobes, those of lateral leaflets unequal, outer lobe large, deltoid, and acute, inner lobe smaller and rounded, margin closely spinose-serrate, apex acuminate. Flowering stem normally with 2 (abnormally 3) trifoliolate opposite leaves. Inflorescence simple, racemose, or compound with lower peduncles loosely 2-or 3-flowered, rachis glandular pubescent, 14-25-flowered, 14-30 cm. Pedicel 1.5-4 cm, glandular pubescent. Flowers purplish red, ca. 2 cm. Outer sepals violet-tinged, narrowly ovate, 3-4 × ca. 1.5 mm, apex blunt; inner sepals reflexed, white or pinkish, narrowly lanceolate, 1.5-1.8 cm × ca. 4 mm, apically acuminate. Petals dark violet, much shorter than inner sepals, slightly 2-or 3-lobed; spur straight, cylindric-subulate, blunt, 7-8 mm. Stamens conspicuously prolonged, ca. 9 mm; anthers purple, 3-4 mm. Ovary ca. 1.3 cm. Capsules included; style ca. 2 cm. Fl. Mar-Apr, fr. Apr-Jun.