found: Plants national database, July 24, 2006(Conyza canadensis (l.) Cronq., Canadian horseweed. Invasive information: Conyza canadensis, horseweed, horseweed fleabane, mares tail)
found: UC IPM online, July 24, 2006(Horseweed, scientific name: Conyza canadensis. Also called mare's tail)
found: HortiPlex database, July 24, 2006(Conyza canadensis, Canadian horseweed, Canada fleabane)
found: Connecticut Botanical Society Connecticut wildflowers Web site, July 24, 2006(Horseweed, Conyza canadensis (Erigeron canadensis))
found: American heritage dict.(horseweed: a weedy North American plant Erigeron canadensis having narrow leaves and numerous small white or greenish flower heads grouped in panicles)
found: Wikipedia, July 24, 2006(Conyza canadensis. Conyza canadensis (formerly Erigeron canadensis) is an annual plant native throughout most of North American and Central America. Comon names include Horseweed, Canadian horseweed, Canadian fleabane, Coltstail, and Butterweed)