马松子 ma song zi

Riedlea corchorifolia (Linnaeus) Candolle; Visenia corchorifolia (Linnaeus) Sprengel.

Herbs or subshrubs, less than 1 m tall, erect or decumbent. Branches yellow-brown, sparsely stellate puberulent. Stipules linear, 2-4 mm; petiole 5-25 mm; leaf blade ovate, oblong-ovate, or lanceolate, rarely obscurely 3-lobed, 2.5-7 × 1-1.3 cm, thinly papery, abaxially sparsely stellate puberulent, adaxially nearly glabrous, basal veins 5, base rounded or cordate, margin
dentate, apex acute or obtuse. Inflorescence a dense cyme or glomerule, terminal or axillary. Epicalyx lobes 4, linear, hairy. Calyx campanulate, 5-lobed, ca. 2.5 mm, abaxially villous and hispid, adaxially glabrous, lobes triangular. Petals 5, white, drying reddish, oblong, ca. 6 mm, narrowed at base. Stamens 5, connate at base, opposite petals. Ovary sessile, densely velutinous; styles 5, filiform. Capsule globose, 5-angular, 5-6 mm in diam., villous. Seeds 1 or 2 per cell, brown-black, ovoid, slightly triangular, 2-3 mm. Fl. summer-autumn.

Widespread weed. S of Chang Jiang [Japan; pantropical].