Description from Flora of China
Portulaca portulacastrum Linnaeus, Sp. Pl. 1: 446. 1753.
Herbs perennial. Stems prostrate or creeping, green or red, 20-50 cm, much branched, often rooting from nodes, with white bladder cells. Leaves linear-oblanceolate or elliptical, 1.5-5 cm × 2-10 mm, below middle attenuate, base broadened into membranous margins clasping stem. Pedicel 5-20 mm. Flowers solitary. Perigone 6-8 mm; tube ca. 2 mm; lobes 5, ovate-lanceolate, outside green, inside pink. Stamens 15-20, connate with perigone tube below middle. Ovary obovate, glabrous; stigmas 3-5. Capsule obovate, shorter than perigone. Seeds shiny black. Fl. Apr-Jul. 2n = 36, 40, ca. 48.
Sands of seashores. Fujian, Guangdong, Hainan (including Nanhai Zhudao), Taiwan [tropical and subtropical regions worldwide].