Galeopsis tetrahit is one of many species in the mint family in Wisconsin. Leaves are simple, toothed and opposite. The corolla is tubular, bilaterally symmetrical and may be white or pink. The calyx lobes have conspicuous spiny tips, which become even stiffer as they mature. The stem is bristly and may have an enlarged area below each node. Each ovary is comprised of four lobes, each of which matures to become a hard, single-seeded nutlet.

This species has been in Wisconsin since at least as early as the 1940's and I have seen it in northern Wisconsin since the 1960's. It seemed to be a disturbed soil, roadside/field/yard kind of a plant and not very aggressive in my experience. However in recent years it has begun to spread from forest roadsides into the adjacent forests and is now clearly a serious invasive. It spreads rapidly along skid trails and new roads, but is also found very widely in mesic forests of northeastern Wisconsin, and perhaps more broadly.