黄车轴草 huang che zhou cao

Trifolium agrarium Linnaeus, nom. utique rej.; T. strepens Crantz, nom. illeg. superfl.

Annual herbs, appressed puberulent. Stems erect or as­cending, branched at middle, (10-)20-50 cm. Leaves palmately 3-foliolate; stipules lanceolate, 1-1.5 cm, veins prominent, ad­nate to petiole for ca. 1/2 their length, apex long acuminate; petioles equal to leaflets in lower leaves, shorter in upper leaves; leaflets obovate-oblong to narrowly elliptic, ± sessile, 10-23 × 5-8 mm, papery, lateral veins 10-18 pairs, base cuneate, mar­gins entire at base, serrate distally, apex obtuse (rarely emargi­nate). Flowers 25-40, imbricate in dense, globose to shortly cylindric racemes, 1.5-2 cm, axillary and terminal; peduncle as long as or longer than racemes; involucre and bracts absent; pedicels ca. 1 mm, reflexed after anthesis. Calyx 2-2.5 mm, veins 5; tube short; lower 3 teeth 2-2.5 × length of upper 2. Co­rolla yellow, turning brown, 6-8 mm; standard elliptic. Ovary long stipitate, oblong; style longer than ovary. Legume nar­rowly ovoid, 2.5-3 mm, stipitate, apex with persistent style. Seed 1, yellow-brown, ellipsoid, 1-1.2 mm. Fl. and fr. Jun-Jul.

Cultivated, escaped, and naturalized; roadsides, weedy areas. He­bei, Jiangsu, Shaanxi [native to SW Asia and C and N Europe].