Description from Flora of China
Herbs perennial. Rhizomes swollen at apex, sometimes with enlarged stolons bearing scalelike leaves. Stems erect, 20-70 cm, usually unbranched, nodes ± tinged purple-red. Leaves subsessile or short petiolate, linear to oblong-lanceolate, ± arcuate, 4-8 × 1.2-2.5 cm, glabrous to minutely hispid-hirsute, abaxially impressed glandular, base attenuate, margin ± pinnatipartite to ± entire, apex acuminate. Verticillasters globose, 1.2-1.5 cm in diam.; bracteoles ovate to lanceolate, ciliolate, spinescent, outermost to 5 mm and 3-veined, inner ones 2-3 mm and 1-veined. Calyx ca. 3 mm, glabrous, glandular; teeth 5, lanceolate-triangular, ca. 2 mm, apex spinescent, ciliolate. Corolla white, ca. 5 mm, glandular, throat white pubescent, tube ca. 3 mm; limb indistinctly 2-lipped, upper lip subcircular; lower lip 3-lobed, middle lobe larger. Nutlets obovoid, 4-sided, ca. 1.6 × 1.2 mm, abaxially flattened, glandular, base subattenuate. Fl. Jun-Sep, fr. Aug-Nov.
Marshy areas, grasslands, streamsides; 300-2600 m. Anhui, Fujian, Gansu, Guangdong, Guangxi, Guizhou, Hebei, Heilongjiang, Hubei, Hunan, Jiangsu, Jiangxi, Jilin, Liaoning, Shaanxi, Shandong, Shanxi, Sichuan, Taiwan, Yunnan, Zhejiang [Japan, Russia]