Fumaria decumbens Thunberg, Nova Acta Acad. Sci. Imp. Petrop. Hist. Acad. 12: 102. 1801; Corydalis amabilis Migo; C. eduloides Fedde; C. eduloides var. haimensis Fedde; C. gracilipes S. Moore; C. kelungensis Hayata; Pistolochia decumbens (Thunberg) Holub.

Tuber rounded, 4-13 mm in diam.; new tubers arising directly on old tuber, mainly from axils of radical leaves. Stems usually several from each tuber, 10-25 cm, slender, weak, simple, with 2 or 3 leaves, without scales. Leaves twice to 3 × ternate; leaflet entire or deeply cut into subacute lobes. Raceme lax, 3-10-flowered; bracts ovate, 5-8 mm, entire. Pedicel 10-20 mm. Flowers nearly white or pale pink, sometimes marked with light blue, smelling like Viola odorata. Sepals caducous. Upper petal 14-18 mm, usually narrowly crested, with spreading limb; spur straight or slightly curved, distinctly shorter than limb; nectary 1/3-1/2 as long as spur, apex acuminate; lower petal broadly spatulate; inner petals with broad, rounded crests exceeding apex. Capsule linear, slightly torulose, 13-18 mm, 6-14-seeded. Seeds keeled, covered with vesicular papillae. Self-compatible. Fl. and fr. Feb-May.

This species is an important herb in traditional Chinese medicine.

A plant possibly related to Corydalis decumbens but more robust with crenately lobed leaflets and larger lobed tuber has recently been recorded in Hunan. We have yet only photographic documentation of this possibly new species.

Mountain slopes, roadsides, wastelands near coast; 100-300 m. Anhui, Fujian, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi (Hua Shan), Taiwan, Zhejiang [S Japan (including Ryukyu Islands)].