7. Trigonella caerulea (Linnaeus) Seringe in Candolle, Prodr. 2: 181. 1825.
蓝胡卢巴 lan hu lu ba
Trifolium caeruleum Linnaeus, Sp. Pl. 2: 764. 1753 [T. "M. caerulea"]; Melilotus caeruleus (Linnaeus) Desrousseaux.
Annual herbs, 30-60(-80) cm. Stems straight, thick, terete, glabrescent, branched. Leaves pinnately 3-foliolate; stipules subulate-lanceolate; petioles 1-4 cm; leaflets ovate to broadly elliptic, 15-35 × 4-15 mm, sparsely pubescent on midrib abaxially, glabrous adaxially, lateral veins 8-10 pairs, base cuneate or rounded, margin serrate, apex obtuse or acute. Racemes capitate or ovoid, 10-25-flowered; peduncles axillary, ca. 6 cm, straight, glabrous; bracts bristlelike, ca. 1.5 mm; pedicel ca. 1 mm. Calyx ca. 3 mm, membranous, veins 5. Corolla blue, 5-6 mm; standard longest petal, keel shortest. Ovary ovate, glabrous; ovules 5-7. Legume ovoid, 2.5-5 × ca. 2.5 mm, apex tapering and beaked, longer than body. Seeds 1 or 2, brown, broadly ovoid, ca. 2 mm, tuberculate. Fl. Jun-Aug, fr. Jul-Sep.
Cultivated or escaped on wastelands. Gansu, Hebei, Heilongjiang, Liaoning, Nei Mongol, Shaanxi [widely cultivated in Asia and Europe; of cultivated origin].
Trigonella caerulea is apparently nowhere indigenous and was probably derived from T. procumbens (Besser) Reichenbach (Ivimey-Cook in Tutin et al., Fl. Eur. 2: 152. 1968).
