Symphyotrichum is a genus of flowering plants in the tribe Astereae which includes the commonly cultivated New York aster (S. novi-belgii) and New England aster (S. novae-angliae). Its species are widespread in the Americas, including as far north as subarctic North America to as far south as Chile, Argentina, and the Falkland Islands. One species has a native range extending into eastern Eurasia. Most of the species in the genus are perennials. The flower heads have white, pink, purple, or blue ray florets surrounding white to yellow disk florets. The disk floret corollas become pink, purple, or brown after pollination. The three species in section Conyzopsis have reduced or absent ray florets. Symphyotrichum is the type genus of subtribe Symphyotrichinae. There are 98 species in the genus, some with varieties, and thirteen named hybrids. The genus is split into five subgenera: Chapmaniana, Astropolium, Virgulus, Ascendentes, and Symphyotrichum. Most of the species had been classified within the genus Aster until it was confirmed to be polyphyletic. The American asters now are separated into monophyletic genera based on multiple phylogenetic studies.
Conventions
Conservation status codes follow the NatureServe conservation (NS) rounded global status scheme. Hybrids have a column for parents in place of conservation status. Not listed (NL) is not a NatureServe category but is used here to represent those left out of global status rankings up to G5 (including GNA and GNR) and those not in NatureServe. Type species for each clade are in a separate table.
Classification
Classification of Symphyotrichum
Classification within Symphyotrichum Most of the species had been classified within the genus Aster until it was confirmed to be polyphyletic – as previously defined, the genus Aster contained groups of species with different most recent ancestors. The American asters were then separated into several genera based on morphological characteristics and phylogenetic studies. Within Symphyotrichum, S. novae-angliae and S. turbinellum are monotypic within sections. S. novae-angliae is classified in the subgenus Virgulus. In 1994, it was placed in section Grandiflori, subsection Polyligulae. In 2002, it was segregated within its own section Polyliguli. The list follows the 2002 circumscription of section Polyliguli for the species. S. turbinellum is classified in the subgenus Symphyotrichum. It has been placed within its own section Turbinelli. It was previously placed in section Symphyotrichum, subsection Turbinelli. The list follows the more recent circumscription of section Turbinelli for the species.
Species list
Subgenus Chapmaniana
Subgenus Astropolium
Subgenus Virgulus Subgenus Virgulus (Raf.) G.L.Nesom
Section Ericoidei
Section Patentes Section Patentes (Torr. & A.Gray) G.L.Nesom
Subsection Brachyphylli
Subsection Patentes
Section Grandiflori Section Grandiflori (Torr. & A.Gray) G.L.Nesom
Subsection Mexicanae
Subsection Grandiflori
Section Polyliguli
Section Concolores
Subgenus Virgulus named hybrids
Subgenus Ascendentes This subgenus contains two allopolyploid species derived from the historic hybridization of plants from the subgenera Symphyotrichum and Virgulus.
Subgenus Symphyotrichum
Section Conyzopsis The three species in section Conyzopsis have reduced or absent ray florets.
Section Occidentales
Section Turbinelli
Section Symphyotrichum
Subsection Dumosi
Subsection Heterophylli Subsection Heterophylli (Nees) Semple
Series Concinni
Series Cordifolii
Subsection Porteriani
Subsection Symphyotrichum
Series Punicei
Series Symphyotrichum
Subgenus Symphyotrichum named hybrids
Notes
Citations
References






