1. Penthorum Linnaeus, Sp. Pl. 1: 432. 1753.
扯根菜属 che gen cai shu
Pan Jintang ; Douglas E. Soltis
Herbs perennial, erect, fibrous rooted. Stems terete, glabrous proximally to finely pubescent and widely branched distally. Leaves alternate, shortly petiolate; leaf blade lanceolate or narrowly so, thin, apex long acuminate. Flowers numerous, arranged in terminal and axillary, scorpioid (or corymblike) cymes, bisexual, yellow-green, small. Sepals 5(-8). Petals 5(-8) or absent. Stamens 10(-16), in 2 whorls. Carpels 5(-8), connate near base; ovules many; styles short. Capsule 5(-8)-lobed; carpels rostrate at apex. Seeds many, small.
Two morphologically very similar species: one in E Asia, the other in E North America; one species in China.
Recent studies have demonstrated that Penthorum is not part of Saxifragaceae, but is actually most closely related to Haloragaceae.