Splitlip hempnettle

Galeopsis bifida (splitlip hempnettle) is an erect, branching annual herb of the mint family (Lamiaceae), growing up to about 1 m tall with characteristic four-angled, bristly stems that are conspicuously swollen and bulbous just below the leaf nodes. Leaves are opposite, ovate to lance-shaped, 2–13 cm long, with coarsely serrate margins and short hairs on both surfaces. From late summer into autumn the plant produces dense whorled clusters of two-lipped bilabiate flowers in the upper leaf axils and at the stem tips; each corolla is about 13–20 mm long in shades of pinkish-purple, white, or pale rose, with a single-lobed hooded upper lip and a hairy three-lobed lower lip bearing a deeply notched (bifid) central lobe that distinguishes it from its close relative G. tetrahit. The fruit is a four-parted brown schizocarp of nutlets, with each plant capable of producing several thousand seeds. Native to Europe and temperate Asia, it has been widely introduced across Canada, the northeastern and midwestern United States, Alaska, New Zealand, and the Canary Islands, growing in disturbed sites, roadsides, gardens, cultivated fields, wet heaths, and damp woodland.