Galeopsis tetrahit L.
Linnaeus, C. (1753). Species Plantarum, Tomus II: 579.
Galeopsis tetrahit (Common Hemp-nettle) is a flowering plant in the family Lamiaceae, native to Europe and northwestern Asia.
It is a herbaceous annual plant growing to 1 m tall; it is a pioneer species and thrives on disturbed sites or roadsides. The plant looks like mint but is taller. The stems have reflexed hairs and swollen nodes. In cross section, the stem is square. The leaves are rhombic to elliptic, with coarsely to bluntly serrate edges. The flowers are purple, diminutive, bilateral and snapdragon-like.
The species is considered by some authorities to have arisen as a natural hybrid between Galeopsis pubescens and Galeopsis speciosa.
Source: Wikipedia, Wikispecies: All text is available under the terms of the GNU Free Documentation License