Erigeron corymbosus is a North American species of flowering plants in the daisy family known by the common name long-leaf fleabane. It is found in western Canada (British Columbia) and the western United States (Washington, Oregon, Idaho, Montana, Wyoming, Utah). Erigeron corymbosus is a perennial herb up to 50 cm (20 inches) tall, forming a taproot. Each branch produces an array of up to 16 flower heads, each head with 35–65 blue or pink ray florets plus numerous yellow disc florets.