Family: Asteraceae

Senecio madagascariensis, commonly known as fireweed or Madagascar ragwort, is a species of flowering plant in the aster family, Asteraceae. It is native to Madagascar but has become naturalized and invasive in various parts of the world, including Australia and the Hawaiian islands of Oahu, Molokai, Lanai, Maui, Kahoolawe, and Hawaii.

Senecio madagascariensis typically grows as a perennial herb, producing erect stems with bright yellow flowers. It is often found in disturbed areas such as roadsides, pastures, and abandoned fields. It can quickly spread by its wind-dispersed seeds, can form high densities in disturbed habitats, and is toxic to livestock.

Due to its invasive nature, Senecio madagascariensis poses a threat to agricultural land and biodiversity in regions where it has become established. Efforts to control its spread often involve herbicidal treatments and mechanical removal, as well as release of natural enemies for biological control.