As written in wikipedia, Aster (syn. Diplopappus Cass.) is a genus of flowering plants in the family Asteraceae. The genus once contained nearly 600 species in Eurasia and North America, but after morphologic and molecular research on the genus during the 1990s, it was decided that the North American species are better treated in a series of other genera.
After this split there are roughly 180 species within the genus, all but one being confined to Eurasia.
The name Aster comes from the Ancient Greek word astron, meaning "star", arriving through the Latin word astrum with the same meaning, referring to the shape of the flower head. 
