Costeroa

Costeroa is a genus of flowering plants in the family Asteraceae, commonly known as the California asters. These plants are native to western North America, primarily California and Baja California. The genus was established by Merritt Lyndon Fernald in 1900, with the type species being Costeroa integrifolia.

Plants in the genus Costeroa are typically herbaceous perennials, though some can be shrubs. They are characterized by their daisy-like flower heads, which usually have white or pale purple ray florets and yellow disc florets. The leaves are often simple and arranged alternately on the stem. These plants are adapted to a variety of habitats, including grasslands, chaparral, and open woodlands, often in well-drained soils.

The taxonomy of Costeroa has been subject to some revision, with some species previously included in the genus now classified elsewhere. Molecular phylogenetic studies have helped to clarify its relationships within the Asteraceae family. Despite taxonomic changes, the genus remains recognized for its distinctive floral morphology and ecological niche within its native range.