Tanacetum parthenium

Native from southeastern Europe to the western Himalayas, this aromatic perennial herb in the daisy family forms leafy clumps about 1 to 3 feet tall. Its deeply lobed leaves accompany clusters of white flower heads with yellow centers. It readily spreads by self-seeding. Traditionally used for fever and headaches, it can cause mouth irritation and allergic skin reactions. It has naturalized in Colombia, where it occurs at about 4,200 to 10,800 feet. Photographed in Bogotá, Colombia.