Aster is agenus ofperennial flowering plants in the familyAsteraceae. Itscircumscription has been narrowed, and it now encompasses around 170 species, all but one of which are restricted toEurasia; many species formerly inAster are now in other genera of the tribeAstereae.Aster amellus is thetype species of the genus and the family Asteraceae.[1]
The nameAster comes from theAncient Greek wordἀστήρ (astḗr), meaning 'star', referring to the shape of theflower head. Many species and a variety of hybrids and varieties are popular as garden plants because of their attractive and colourful flowers. 'Aster' species are used as food plants by thelarvae of a number ofLepidoptera species—see list of Lepidoptera that feed onAster. Asters can grow in all hardiness zones.
The genusAster once contained nearly 600 species in Eurasia and North America, but aftermorphologic 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 related genera. After this split there are roughly 180 species within the genus, all but one being confined to Eurasia.[3]
Aster alpinus is the only species ofAster (sensu stricto) that is native to North America; it is found in mountains across the Northern Hemisphere.
Plants of the World Online accepts 186 species as of August 2024.[2] The species formerly known asAster tripolium (sea aster) is nowTripolium pannonicum. The species formerly known asAster linosyris (goldilocks) is nowGalatella linosyris. Many species and a variety of hybrids and varieties are popular as garden plants because of their beautiful, attractive and colourful flowers.Aster species are used as food plants by the larvae of a number ofLepidoptera species—see list of Lepidoptera that feed onAster. Asters can grow in all hardiness zones.
One of the few flowers left aroundMichaelmas in theBritish Isles is the Michaelmas daisy (another name for asters), hence the rhyme: "The Michaelmas daisies, among dead weeds, Bloom for St Michael's valorous deeds..."[15]
