牛至 niu zhi

Origanum creticum Loureiro; O. normale D. Don; O. vulgare var. formosanum Hayata.

Rhizomes oblique, ± woody. Stems erect or prostrate near base, 25-60 cm, purplish, retrorse pubescent or slightly floccose-pubescent, numerous, leafless near base, lower branches sterile. Petiole 2-7 mm; leaf blade ovate to oblong-ovate, 1-4 × 0.4-1.5 cm, glandular, adaxially shiny green tinged purple, sparsely villous, abaxially densely villous, base broadly cuneate to rounded, margin entire or remotely serrulate, apex obtuse to slightly obtuse. Spikes oblong, ± elongated in fruit; floral leaves mostly sessile, purplish; bracts green or purple, oblong-obovate to obovate or oblanceolate, ca. 5 mm, margin entire, apex acute. Calyx ca. 3 mm, minutely hispid or subglabrous; teeth triangular, ca. 0.5 mm. Corolla purple-red to white, tubular-campanulate, 5-7 mm; tube ca. 5 mm, exserted in bisexual flowers, ca. 3 mm, included in pistillate flowers, sparsely pubescent; upper lip ovate, ca. 1.5 mm, apex 2-lobed; lower lip ca. 2 mm, lobes oblong-ovate. Nutlets brown, ca. 0.6 mm, apex rounded. Fl. Jul-Sep, fr. Oct-Dec.

Hills, grasslands, forests; 500-3600 m. Anhui, Fujian, Gansu, Guangdong, Guizhou, Henan, Hubei, Hunan, Jiangsu, Jiangxi, Shaanxi, Sichuan, Taiwan, Xinjiang, Xizang, Yunnan, Zhejiang [Kazakhstan, Kyrgyzstan, Russia; Africa, Europe, introduced in North America]

A polymorphic species; used medicinally.