Mint family (Lamiaceae)
Perennial of heights 30-100 cm, with erect stem square in cross-section and downy, branched above. Leaves opposite, broad, cordate-ovate and sharp-pointed, as well as hairy. Leaf blade 4-9 cm long. Flowers in groups of 2-6 in verticillasters, forming an apical-spike inflorescence. Calyx with sharp-pointed segments. Irregular two-lipped corolla dark red in colour, with pale streaks, length 12-18 mm. Flowers Jun.-Sep.
Grows in moist fertile soils, in riparian and oak-lime-hornbeam forests. Whole plant smells unpleasant, though used medicinally.
Descriptions devised by the team at the Independent Department of Forest Botany, Warsaw University of Life Sciences, i.e. L. Witkowska-Żuk, K. Marciszewska, W. Ciurzycki, A. Obidziński and P. Zaniewski.