This genus of annuals and herbaceous perennials originates from North and South America, with a centre of diversity in Mexico. Comprising around 50 species, they are annual or perennial herbaceous plants with aromatic leaves and daisy-like flowers in summer and autumn. They are cultivated widely for their attractive pinnate divided leaves and showy flowers, that come in a variety of hot colours and patterns. They are also used in companion planting to deter pests from food crops, as well as growing well in containers - and are also long-lasting as cut flowers.