Description from Flora of China
Pulegium vulgare Miller.
Herbs. Stolons with scalelike leaves. Stems ascending, rarely erect or trailing, 15-30(-50) cm, hirtellous, striate, tinged red-purple, much branched, internodes generally longer than leaves. Leaf blade ovate-orbicular to ovate, 0.8-1.3 cm × 5-7 mm, herbaceous, puberulent, base rounded, margin entire or sometimes remotely crenate, apex obtuse. Verticillasters 10-30-flowered, globose, 1-1.5 cm in diam., few, widely spaced; floral leaves sessile, recurved, shorter than verticillasters. Pedicel 2-3 mm. Calyx tubular, 2-lipped, 2.5-3 mm, hirtellous, glandular, throat bearded, ± conspicuously 10-veined, tube ca. 1.5 mm; upper lip 3-toothed, teeth lanceolate-triangular, ca. 1 mm; lower lip 2-toothed, teeth subulate, ca. 1.5 mm. Corolla rose, purple or rarely white, ca. 4.5 mm, puberulent; tube ca. 3 mm, abruptly saccate at apex; lobes oblong, ca. 1.5 mm, entire, upper lanceolate. Ovary glabrous. Fl. Sep.
Cultivated in China. Source of oil of pennyroyal. Employed in the manufacture of soaps and synthetic menthol. Used medicinally for flatulent colic, stomach ailments, and as a diaphoretic.
Beijing Shi, Nanjing Shi, and other cities [Russia, Tajikistan, Turkmenistan; SW Asia, Europe]