2. Lamium amplexicaule L., Sp. Pl. 579. 1753. Benth. in DC., Prodr. 12: 508. 1848; Hook. f., Fl. Brit. Ind. 4: 679. 1885; Mukerjee in Rec. Bot. Surv. Ind. 14, 1: 161. 1940; Hedge & Lamond in Notes Roy. Bot. Gard. Edinb. 28: 89. 1968; Stewart, Ann. Cat. Vasc. Pl. W. Pak. & Kashm. 614. 1972; Sharma & Kachroo, Fl. Jammu 262. 1981; Mennema in Roth. f., Fl. Iran. 150: 328. 1982; Kaul, Weed Fl. Kashmir valley 239. 1986; Mennema in Leiden Bot. Ser. 11: 48. 1989.
Annual, usually slender. Stems erect, ascending or prostrate often branched from the base, 10-40 cm, almost glabrous or with a sparse indumentum of short usually retrorse eglandular hairs, purplish below or not, with few leaves. Leaves broadly ovate to reniform, c. 10-20 x 10-20 mm, crenate to lobed, obtuse, rounded or cordate at base, pubescent; petiole of basal leaves 10-20 cm. Verticillasters 1-5, distant, up to 16-flowered, almost hidden by enclosing amplexicaul leaves. Bracts present or absent. Calyx 4-7 mm narrow tubular, ± densely pubescent with eglandular hairs; teeth narrow triangular, acuminate, about as long as tube, equal, converging in fruit. Corolla purple-pink, 15-20 mm; upper lip pubescent to vinous, straight; lower lip reflexed, shorter than upper; tube slender, straight, c. 0.8 mm in width, exannulate. Stamens included under corolla upper lip. Nutlets c. 2-2.5 x 1-1.5 mm, smooth, with a short broad-based stipe, dearly trigonous below, brown, apically rounded, usually with numerous white raised blotches, not mucilaginous on wetting.
Fl. Per.: December-April.
Type: Europe (LINN 733/12 microfiche!).
Distribution: Throughout Europe and Asia. An introduced weed in other parts of the world, such as South Africa.
Usually found as a field weed. Forms with cleistogamous flowers occur throughout the total range of the species; in such cases the closed flowers are only about 5 mm long.