Ruysch's snakehead (lat. Dracocephalum ruyschiana)
Perennial herbaceous plant with branched rhizome, 40–60 cm high; several stems, erect. The leaves are sessile, lanceolate-linear or linear, obtuse, with entire, complete edges, dark green above, shiny, lighter below, with pinpoint glands.
The inflorescence is spike-shaped, more or less dense, short (round or short-oval). The bracts are ovate-lanceolate, pointed. The upper tooth of the calyx is 1.5–2 times wider than the others. Corolla 20–28 mm, bright blue. Blooms in summer.