Composite Family (Compositaceae)

The composite or aster family (Asteraceae) is one of the largest families of plants, containing about 20,000 species, distributed among more than 1,000 genera, and occurring widely on all continents, except Antarctica. This family is commonly regarded by modern botanists as the most advanced of the plant families, because of the complex, highly evolved structure of its multi-flowered, composite reproductive structures.

The members of the composite family display a remarkable range of growth forms, ranging from tiny, herbaceous annual plants, to vine-like lianas, and tall, tree-like perennials. For example, some species in the genus Senecio are small, annual plants, such as the widespread common groundsel (Senecio vulgaris). In contrast, the giant senecio (S. adnivalis) species found on a mountain in Uganda, is a perennial plant that grows as tall as 26 ft (8 m).

The most species-rich genera in the aster family are Senecio (about 1,500 species), Vernonia (900 species), Hieracium (800 species), and Eupatorium (600 species). Various members of the aster family are familiar species in natural habitats, while others are cultivated plants in gardens, and some are grown as foods. Some species in the aster family are considered to have negative values as weeds of agriculture or lawns.