Lamium X cardiaca Cogniaux, found before 1815 in Belgium near Kanne by Nyst, and considered by its author to be the hybrid of Lamium maculatum and Leonurus cardiaca, falls within the variability of L maculatum L. It has also been found in the Netherlands between Mook and Middelaar (prov. Limburg) and described as L. maculatum L. f. trilobum Joh. Jansen in Ned. Kruidk. Arch. 1930, p. 223.