Description from Flora of China
Mentha spicata var. viridis Linnaeus; M. viridis (Linnaeus) Linnaeus.
Herbs stoloniferous. Stems erect, 40-130 cm, glabrous or subglabrous, striate. Leaves sessile or subsessile, ovate-oblong to oblong-lanceolate, 3-7 × 1-2 cm, base broadly cuneate to rounded, margin irregularly serrate, apex acute. Verticillasters in cylindric terminal spikes 4-10 cm, spikes interrupted at base; bracteoles linear, 5-8 mm. Pedicel ca. 2 mm. Calyx campanulate, ca. 2 mm, glandular, obscurely 5-veined; teeth triangular-lanceolate, ca. 1 mm. Corolla purplish, ca. 4 mm, glabrous, tube ca. 2 mm; lobes subequal, apex emarginate. Ovary brown, glabrous. Fl. Jul-Sep.
Cultivated in China. Source of spearmint oil, an essential oil used for flavoring candies, toothpaste, chewing gum. Dried tops and leaves are used medicinally as a stimulant, carminative, and nervine. It contains carvone.
Guangdong, Guangxi, Guizhou, Hebei, Hubei, Jiangsu, Sichuan, Xizang, Yunnan, Zhejiang [Russia, Turkmenistan; Africa, SW Asia; Europe]