1. Lathyrus davidii Hance, J. Bot. 9: 130. 1871.
大山黧豆 da shan li dou
Herbs perennial, with tuberous roots, 1-1.8 m tall. Stem strong, erect or decumbent, glabrous, wingless, hollow in lower parts. Leaves with strong, branched tendrils; stipules large, often similar to leaflets, semisagittate, ovate, 40-60 mm, entire or sometimes dentate at base; leaflets (2 or)3- or 4(or 5)-paired, usually ovate, 40-70 × 50-110 mm, glabrous, with reticulate veins, margin entire, apex mucronate. Raceme subequaling leaf, 10-40-flowered. Calyx campanulate, ca. 5 mm, glabrous, shortly toothed. Corolla yellow, maturing to orange, 1.5-2 cm; standard elliptic, with claw; wings subequaling standard, auriculate at base. Ovary linear, glabrous. Legume orange-brown, linear, 8-15 cm. Seeds purple-brown, broadly oblong, smooth. Fl. May-Jul, fr. Aug-Oct.
Forest margins, scrub forests, slopes; below 1800 m. Anhui, Gansu, Hebei, Heilongjiang, Henan, Hubei, Hunan, Jilin, Nei Mongol, Shaanxi, Shandong, Shanxi [Japan, Korea, Russia].