This common annual weed is widespread across temperate North America. In Ky. it was recorded early after settlement (McMurtrie 1819). Short (1837) noted: "A troublesome weed, occurring everywhere in neglected and uncultivated grounds." Ancient medicinal and culinary uses were apparently ignored. Most Ky. material matches var. leiocarpum DC., but that segregate has generally not been recognized in recent treatments. Colls. from MEAD (DHL) and MERC (KY) would match the typical variety.