It is now abundantly clear that the traditional, broad circumscription of Aster, as a genus of some 250 species of North America and Eurasia, is untenable. All of our native asters have affinities elsewhere than with Old World Aster; most are now placed in Symphyotrichum and Eurybia, with fewer species in Ampelaster, Doellingeria, Ionactis, Oclemena, and Sericocarpus. These changes will undoubtedly cause uproar. It may be worth noting for those that consider the dissolution of Aster as radical, that most of the segregate genera were recognized in the 19th century, and many have been widely recognized for much of the time since. For instance, Sericocarpus and Doellingeria were both segregated from Aster in the early 1830’s, and were frequently recognized as distinct, including by Small (1903, 1913, 1933); Sericocarpus was in fact usually regarded as a good genus until sunk by Cronquist.
Ref: Brouillet (2006d) In Flora of North America Editorial Committee (2006b); Brouillet & Semple (1981); Cronquist (1980); Jones (1980a); Jones (1980b); Jones (1984); Jones (1992); Jones & Young (1983); Lamboy (1992); Nesom (1993a); Nesom (1993b); Nesom (1994a); Nesom (1994a); Nesom (1994b); Nesom (1997a); Nesom (2000b); Noyes & Rieseberg (1999); Reveal & Keener (1981); Semple & Brouillet (1980a); Semple & Brouillet (1980b); Semple, Chmielewski, & Lane (1989); Semple, Heard, & Xiang (1996); Semple, Heard, & Xiang (1996); Small (1903); Xiang & Semple (1996). Show full citations.