Symphyotrichum

Symphyotrichum (/ˌsɪmfaɪəˈtrɪkəm/) is a genus of over 90 species of herbaceous annual and perennial plants in the composite family (Asteraceae) that were formerly treated within the genus Aster. The majority are endemic to North America, but several species also occur in the West Indies, Central and South America, as well as in eastern Eurasia. Many species have been introduced to Europe as garden specimens, most notably New England aster (Symphyotrichum novae-angliae) and New York aster (Symphyotrichum novi-belgii).[1][2]

Symphyotrichum
Symphyotrichum novi-belgii
Scientific classification
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Eudicots
Clade: Asterids
Order: Asterales
Family: Asteraceae
Subfamily: Asteroideae
Supertribe: Asterodae
Tribe: Astereae
Genus: Symphyotrichum
Nees
Type species
Symphyotrichum novi-belgii
Nees
Species

See List of Symphyotrichum species.

Description

Brouillet, et al. wrote:

Taxonomy of Symphyotrichum is difficult. Species are usually heterophyllous, some strongly so. Individuals in the spring, with basal rosettes, often have leaf shapes quite different from those with cauline leaves seen later in the season. Phyllary shape on first- and later-formed heads may differ. Individuals may vary considerably in plant size and array development depending upon growing conditions. The genetic diversity within each species also appears considerable.[1]

For all species in the genus, the ray florets are white, pink, blue, or purple. Disc florets are yellow to white, becoming pinkish, reddish purple, or brown when mature. There are 5 lobes on the disc florets of all species in the genus.[1]

Taxonomy

The botanist Christian Gottfried Daniel Nees von Esenbeck established this genus in 1833 because he felt that a plant he examined, now thought to be a cultivated variety of New York aster, was sufficiently distinct from the rest of the genus Aster to warrant its own genus. He emphasized the uniqueness of this plant in having its pappus hairs arranged in a coherent, basal ring.[3] This structure is the basis for the scientific name of this genus, which derives from Ancient Greek σύμφυσις (sýmphysis) "growing together" and θρίξ (thríks; stem τριχ- trich-) "hair". Unfortunately, this characteristic ring is not generally shared by most New York aster pappi, nor is it characteristic of any other plants included in the modern concept of Symphyotrichum. According to the rules of the ICN, however, the timing of this genus's establishment gives it precedence over other names.[4]

This genus was resurrected in 1994 by Guy Nesom to group together species formerly included in Aster in order to make modern genera monophyletic.[4]

Subdivisions

Symphoytrichum has been divided into five subgenera:

Subgenus Ascendentes

This subgenus includes two species from the western United States and Canada that originated as hybrids between species in the subgenera Symphyotrichum and Virgulus.[1][5]

Subgenus Astropolium

This subgenus includes about 10 species found across the Americas in salt marshes and salt flats.[1][6]

Subgenus Chapmaniana

This subgenus includes a single species, S. chapmanii, found in Alabama and Florida.[1]

Subgenus Symphoytrichum

This subgenus includes about 65 species occurring across North America, including a few species in Central America and the Caribbean, with one species also occurring in Eurasia.[1]

Subgenus Virgulus

This subgenus includes about 25 species occurring across North America, including a few species in Central America and the Caribbean.[1]

Distribution

As a whole, Symphyotrichum is native throughout the Americas, with one species, S. ciliatum, also native to eastern Eurasia. Several species have been introduced to Europe and other parts of the world.[1] Most species are native to Mexico, the United States, and Canada, with several species occurring in the West Indies and Central America.[1][7][8][9] Most members of subgenus Astropolium are restricted to South America.[6][10]

Species
Main article: List of Symphyotrichum species

Catalogue of Life lists 106 accepted species and identified naturally-occurring hybrids, including:[11]

References
  1. Brouillet, L.; Semple, J.C.; Allen, G.A.; Chambers, K.L.; Sundberg, S.D. (2006). "Symphyotrichum". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). 20. New York and Oxford. Retrieved 4 November 2020 – via eFloras.org, Missouri Botanical Garden, St. Louis, MO & Harvard University Herbaria, Cambridge, MA.
  2. Everitt, J.H.; Lonard, R.L.; Little, C.R. (2007). Weeds in South Texas and Northern Mexico. Lubbock: Texas Tech University Press. ISBN 0-89672-614-2.
  3. Nees von Esenbeck, C.G.D. (1833). Genera et species asterearum [Genera and Species of the Astereae] (in Latin). Nuremberg: Leonardi Schrag. p. 135. doi:10.5962/bhl.title.46989 – via Biodiversity Heritage Library.
  4. Nesom, G.L. (1995). "Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species". Phytologia. 77 (3): 141–297. ISSN 0031-9430. Retrieved 24 December 2020 – via Biodiversity Heritage Library.
  5. Semple, J.C. "Symphyotrichum subg. Ascendentes". University of Waterloo (UWaterloo.ca). Waterloo, Ontario, Canada: University of Waterloo. Retrieved 6 December 2020.
  6. Semple, J.C. "Symphyotrichum subg. Astropolium". University of Waterloo (UWaterloo.ca). Waterloo, Ontario, Canada: University of Waterloo. Retrieved 6 December 2020.
  7. Gann, G.D. (2021). "Symphyotrichum lucayanum (Britton) G.L. Nesom - Pineland aster". Floristic Inventory of the Bahama Archipelago Database Online (BETA). Delray Beach, Florida: The Institute for Regional Conservation. Archived from the original on 27 January 2021. Retrieved 27 January 2021.
  8. Britton, N.L. (January 1914). "Studies of West Indian Plants-V". Bulletin of the Torrey Botanical Club. 41 (1): 1–24. doi:10.2307/2479432. Retrieved 27 January 2021 – via JSTOR.
  9. POWO (2019). "Symphyotrichum leone (Britton) G.L.Nesom". Plants of the World Online (powo.science.kew.org). Royal Botanic Gardens, Kew. Retrieved 2 December 2020.
  10. Hind, N.; Strange, K. (4 January 2019). "Symphyotrichum vahlii". Curtis's Botanical Magazine. 35 (4): 380–395. doi:10.1111/curt.12259.
  11. Hassler, M. (1 December 2020). "Symphyotrichum Nees". World Plants: Synonymic Checklists of the Vascular Plants of the World (version Sep 2020). Retrieved 27 January 2021 – via Species 2000 & ITIS Catalogue of Life, 2020-12-01 (Roskov, Y.; Ower, G.; Orrell, T.; Nicolson, D.; Bailly, N.; Kirk, P.M.; Bourgoin, T.; DeWalt, R.E.; Decock, W.; van Nieukerken, E.J.; Penev, L.; eds.). Digital resource at Catalogue of Life (www.catalogueoflife.org). Species 2000: Naturalis, Leiden, the Netherlands. ISSN 2405-8858.


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