2. Mentha arvensis L., Sp. Pl. 577. 1753. Benth. in DC., Prodr. 12: 171. 1848; Hook. f., Fl. Brit. Ind. 4: 648. 1885; Briquet in Bull. Soc. Bot. Geneve 5: 42. 1889; Mukerjee in Rec. Bot. Surv. Ind. 14, 1: 86. 1940; Wealth of India, Raw Materials 6: 338. 1962; Tscherneva in Grubov et al., Pl. As. Central. 5: 91. 1970; Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 617. 1972; Tucker et al. in Taxon 29: 236. 1980; Rech. f., Fl. Iran. 150: 556. 1982.
Vern.: Field mint; corn mint; "Podina".
Perennial with white creeping rhizomes. Stems erect or ascending, simple or branched above, often purplish below, quadrangular, leafy, with a ± sparse indumentum of eglandular simple, usually retrorse, hairs. Leaves ovate to ovate-elliptic, 2-5 x 1.2-2 cm, serrulate to serrate, acute, cuneate, on both surfaces with ± adpressed eglandular hairs, gland-dotted below; petiole up to 10 mm on lower leaves. Flowers all in axils of middle and upper leaves. Verticillasters all distant, many-flowered, sub-globose, c. 1.5 cm in diameter. Bracts linear-lanceolate, longer than the c. 2-3 mm erect-spreading pedicels. Calyx tubular-campanulate, 2-3 mm, pilose with eglandular hairs, gland-dotted or not; teeth subequal, triangular, c. 0.5 mm, scarcely acuminate; fruiting calyx scarcely enlarging, green, brown or pinkish. Corolla white or pale lilac, 4-4.5 mm; tube rather broad, as long as calyx or slightly exserted; lobes ± erect, broad, rounded. Nutlets 4, globose c. 1 x 1 mm, smooth, rounded.
Fl. Per.: July-September.
Lectotype (selected by Tucker et al., l.c. 236 and fig. 8): in herb Linnaeus (S).
Distribution: throughout Eurasia and into tropical Asia.
Uncommon, or at least seldom-collected, in our area. Easily distinguished by all the verticillasters borne in the axils of the middle/upper leaves and the glabrous-throated calyx.