1. Polycarpaea corymbosa (Linnaeus) Lamarck, Tab. Encycl. 2: 129. 1797.
白鼓钉 bai gu ding
Achyranthes corymbosa Linnaeus, Sp. Pl. 1: 205. 1753.
Herbs annual or short-lived perennial. Stems erect, 15--35 cm tall, mostly branching above middle, occasionally branched at base, white pilose. Stipules ovate-lanceolate, 2--4 mm, scarious, margin hyaline, apex acute. Leaves apparently verticillate; leaf blade linear or acicular, 1.5--2 cm × ca. 1 mm, erect or uniformly recurved from erect base, apex acute to needlelike. Bracts lanceolate, longer than pedicel, hyaline, membranous. Pedicel slender, white pilose. Sepals lanceolate, (2--)2.7--3.5 × 0.5--1 mm, membranous, hyaline, apex acuminate. Petals milky white or reddish, broadly ovate, ca. 1/2 as long as sepals, apex obtuse. Stamens usually 5, shorter than petals. Style short, 1/3--1/2 as long as ovary. Capsule brown, ovoid, ca. 1/2 as long as calyx, 5--13-seeded. Seed brown, flat, ca. 0.5 × 0.3 mm, obscurely reticulate. Fl. Jul--Aug, fr. Sep--Oct.
Mostly on open, often moist, sandy soils, less often in grassy places on mountain slopes; sea level to 1200 m. Anhui, Fujian, Guangdong, Guangxi, Hainan, Hubei, Jiangxi, Taiwan, Yunnan [widespread throughout tropics and subtropics, most variable and probably originating in Africa].
This species is used medicinally.