A perennial herb with long, thin rhizomes and stalks of 8 to 50 cm Stems weak, ascending, rooting at the bottom. The leaves are opposite, linear or linear-lanceolate, up to 5 cm and a width of 5 mm, sharp, finely spaced, with teeth toward the base sheet and the glands under the teeth, sessile. Flowers in rare flowered brush, located in the axils of leaves (only one of the two opposite). Pedicels filiform, several times higher than a cup. Bracts lanceolate. Calyx with four lobes lanceolate, 2-3 times shorter than the corolla and boxes. Corolla pale blue or off-white, with pink or dark blue stripes, 4-7 mm in diameter, with four blunt blades: two round (top and bottom) and two ovate (side). Fruits — flattened ovoid or kidney-shaped box with a width (4-5 mm), exceeding the length, two-lobed, glubokovyemchatye, flat seeds. It flowers from June to September, the fruits ripen in July and October.
Prevalent in many regions of Eurasia. In our country grows in the European part, Siberia and the Far East. In Central Russia met in all areas. It grows in damp meadows, along the banks of ponds, swamps.