Stachys palustris L. - Clown's Woundwort, Marsh Woundwort.
Systematic position.Family Lamiaceae, genus Stachys L.
Synonyms.Stachys maeotica Postr.
Biological group.Perennial weed with creeping rhizome.
Morphology and biology.Stem erect, tetrahedral, edges with bristly hairs, up to 30-120 cm tall. Leaves opposite, oblong-lanceolate, dentate at edges, with accumbent hairs; lower leaves short-petiolate; upper leaves sessile, enclosing stem. All leaves nearly hairless or with short, bristly hairs. Inflorescence spike-shaped with sparse whorls at base and connivent ones higher up and 6-10 flowers. Calyx markedly bilabiate with glandular hairs and 5 triangular, subulate teeth equal in length to, or shorter than, the tube. Corolla purple or dark pink, bilabiate, two times longer than calyx, with straight hairless tube; lower labium of the corolla is two times longer than the upper one and has three rounded lobes. Nutlets smooth, obovate, 1.6-2.0 mm long, 1.3-1.5 mm wide, rounded apicad, unequally trihedral at base; their color is dark brown to brownish red. Weight of 1000 nutlets is 1.5-2 g. The fruitfulness of one plant is 700 nutlets. Flowering occurs in June-September.
Distribution.Occurs throughout Western Europe, Scandinavia, the Mediterranean area, Asia Minor, Iran, Mongolia, China, Japan, the European former USSR, the Caucasus, Central Asia, Western Siberia, Eastern Siberia, and the Far East.
Ecology.Prefers humid soils. Shoots emerge at minimum temperatures of +8-10°C; optimum temperature is +22-25°C.
Economic significance.Weed of grain, tilled crops, and fodder grasses; occurs in fallow lands, kitchen gardens, wastelands, and along roads. Control measures include multi-field crop rotations; removing the soil to depths of 10-12 cm, followed by under-winter plowing and spring re-plowing or a combination of autumnal removal of the soil and spring plowing; inter-row cultivation of tilled crops; and chemical weeding.
Related references:Agaev, M.G., ed. 1988. Main agricultural weeds in crops of the Leningrad Region. Catalogue of VIR world collection. Issue 468. Leningrad: VIR, 112 p. (in Russian).
Shishkin, B.K., ed. 1954. Flora of the USSR. V. 21. Moscow-Leningrad: AN SSSR, 704 p. (in Russian).
Shishkin B.K., ed. 1963. Botanical atlas. Moscow & Leningrad: Izd-vo sel.skokhozyaistvennoi literatury, zhurnalov i plakatov, 504 p. (in Russian).
Veselovs.kii, I. V., Lisenko, A.K., Man.ko, Yu.P. 1988. Atlas-synopsis of weeds. Kyiv: Urozhai, 72 p. (in Ukrainian).