18. Stachys arvensis Linnaeus, Sp. Pl., ed. 2. 2: 814. 1762.
田野水苏 tian ye shui su
Herbs annual. Stems slender, suberect to decumbent, 30-50 cm, sparsely puberulent, much branched. Stem leaves petiolate; blade ovate, ca. 2 × 1 cm, adaxially sparsely puberulent, abaxially densely pubescent, sparsely puberulent on veins, base cordate, margin crenate, apex obtuse. Verticillasters 2(-4)-flowered, widely spaced; upper floral leaves sessile, base cuneate, margin ± entire, shorter than calyx; bracteoles ca. 1 mm. Pedicel ca. 1 mm. Calyx tubular-campanulate, ca. 3 mm, densely puberulent, 10-veined; teeth subequal, lanceolate-triangular, ca. 1 mm, apex acute; fruiting calyx urceolate, conspicuously netted. Corolla red, ca. 3 mm, nearly included; upper lip ovate, ca. 1 mm, puberulent outside; lower lip spreading, pubescent outside; middle lobe largest, circular; lateral lobes ovate. Nutlets brown, ovoid, ca. 1.5 mm. Fl. and fr. year round.
Weed in waste areas adjacent to cultivated land. Fujian, Guangdong, Guangxi, Taiwan [Russia; Europe, North America, South America].