About Symphyotrichum expansum (Poepp. ex Spreng.) G.L.Nesom
Southwestern annual saltmarsh aster, Symphyotrichum expansum, usually flowers from July through November, and sometimes its flowering period extends into January. Its flower heads have white, and sometimes pink, ray florets that surround yellow disk florets. After pollination, as the plant dries, each individual ray floret curls into 1 to 2 coils. This species is listed under the synonym Symphyotrichum parviflorum in records of its native distribution: it is native to Mexico, the Caribbean, most of Central America, Ecuador, and the southwestern United States. It has been introduced as a non-native species to central Europe. The Flora of North America documents additional introductions of this species in Hawaii and Japan. It grows in marshy habitats and along roadsides, at elevations ranging from 0 to 1,100 meters (0 to 3,600 feet), and sometimes can be found growing as high as 4,000 meters (13,100 feet). It is often categorized as a weedy plant.
