Senecio

Senecio is a genus of flowering plants, family Asteraceae, commonly called groundsels and ragworts; Plants of the World Online currently recognizes 1,482 species, though the exact number remains uncertain due to ongoing taxonomic revisions, and despite recent genetic-based reorganization the genus remains polyphyletic and is one of the largest flowering plant genera. The genus has an almost worldwide distribution and is one of the few genera occurring in all five regions with a Mediterranean climate, with species also found in mountainous and tropical alpine-like regions. Members include annual or perennial herbs, shrubs, small trees, aquatics or climbers, with flower heads typically yellow and often ray-shaped, though the type species lacks ray florets; all species contain pyrrolizidine alkaloids that act as natural pesticides deterring herbivores, and livestock generally avoid the plants for their unpalatability.