Callistephus Cass.
Callistephus is a monotypic genus and originally native in China. It is a segregate of Aster but readily distinguished by its double pappus (outer series of short, bristle-like squamellae) and a distinct involucre of foliaceous outer bracts and white-scarious inner bracts. Its only species, Callistephus chinensis (Chinese aster), is a popular ornamental plant (but perhaps less so in recent times).
Literature:
Jäger E.J., Ebel F., Hanelt P. & Müller G. (eds.) (2008) Rothmaler Band 5. Exkursionsflora von Deutschland. Krautige Zier- und Nutzpflanzen. Springer Verlag, Berlin: 880 p.
Nesom G.L. (2000) Generic conspectus of the tribe Astereae (Asteraceae) in North America, Central America, the Antilles, and Hawaii. Sida Bot. Misc. 20: 80 p.
Nolting G. (1962) Das Sommerastern-Sortiment. Gartenwelt 62: 52-53.