药水苏 yao shui su

Betonica glabrata K. Koch; Stachys betonica Bentham; S. officinalis (Linnaeus) Trevisan de Saint-Leon ex Briquet.

Plants rhizomatous. Stems 50-100 cm, striate, densely fine pilose. Petioles of stem leaves 4-7.5 cm; basal leaf blade broadly ovate, 8-12 × 3-5 cm, pilose, base deeply cordate, margin crenate, apex obtuse; stem leaf blade ovate, 4.5-5.5 × 3-4 cm, widely spaced. Spikes ca. 4 cm, compact, oblong; lower verticillasters sometimes ± widely spaced; basal floral leaves sessile, oblong-lanceolate, ca. 2.5 × 1 cm, margin dentate, apex acute; upper floral leaves linear, margin entire, ca. 6.5 mm; bracteoles ovate to linear, ca. 6.5 mm, abaxially puberulent, margin densely pilose, adaxially glabrous, apex rigidly acute. Flowers subsessile. Calyx ca. 6.5 mm, densely pilose; teeth narrowly triangular, ca. 2.5 mm, pilose. Corolla purple, ca. 1.2 cm, puberulent except for base outside; tube cylindric, ca. 8 mm; upper lip oblong, ca. 4 × 2.5 mm, emarginate, undulate; lower lip oblate, ca. 4 × 6 mm; middle lobe to 4 mm in diam., broadly ovate, undulate; lateral lobes ovate, ca. 1.5 mm wide. Stamens nearly included; filaments puberulent. Ovary black-brown, glabrous. Fl. May.

Cultivated in China [SW Asia, Europe].