白背野扁豆 bai bei ye bian dou

Phaseolus incanus Zollinger & Moritzi, Syst. Verz. 4. 1846; Dunbaria harmandii Gagnepain; D. nivea Miquel.

Herbs. Stems twining, densely villous. Leaves pinnately 3-foliolate; stipules small, deciduous; petiole 4-8(-11) cm, densely tomentose; terminal leaflet rhomboid, 5-7(-9.5) × 4.5-6.5 cm, abaxial surface tomentose, with obvious dark brown sessile glands, basal veins 5, lateral veins 2-4 pairs, visible from both sides, base broadly cuneate, rounded, or nearly truncate, margin slightly sinuate, apex acuminate to acute; lateral leaflets smaller, obliquely ovate, apex mucronate. Racemes axillary or lateral, robust, 5-15 cm, densely villous; bracts ovate-lanceo­late, deciduous; pedicel 2-5 mm, densely tomentose. Calyx campanulate, 5-8 mm, tomentose, with red glands; lobes trian­gular, unequal, lowest longest, shorter than tube. Corolla pur­ple; standard oblate, with 2 acute auricles at base; wings obo­vate-oblong, base with obtuse auricles; keels curved to semicir­cular. Ovary sessile, filiform, villous and red glandular. Legume linear-oblong, 4-6.5 × 0.7-0.9 cm, tomentose, apex with beak 2-3 mm; stipe absent. Seeds 6-8, almost circular, ca. 5 mm in diam. Fl. Feb-Apr, fr. May-Jun.

Open forests. Hainan [Indonesia (Java), Laos, Malaysia, Thailand, Vietnam].