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Symphyotrichum ontarionis
Conservation status
Secure  (NatureServe)
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Asterales
Family:	Asteraceae
Tribe:	Astereae
Subtribe:	Symphyotrichinae
Genus:	Symphyotrichum
Subgenus:	Symphyotrichum subg. Symphyotrichum
Section:	Symphyotrichum sect. Symphyotrichum
Species:	S. ontarionis
Binomial name
Symphyotrichum ontarionis (Wiegand) G.L.Nesom
Varieties
S. ontarionis var. ontarionis S. ontarionis var. glabratum (Semple) Brouillet & Bouchard
Native distribution
Synonyms
Alphabetical list Aster diffusus var. thyrsoideus A.Gray Aster lateriflorus var. thyrsoideus E.Sheld. Aster missouriensis var. thyrsoideus Wiegand Aster ontariensis Wiegand Aster ontarionis Wiegand Aster pantotrichus S.F.Blake Aster pantotrichus var. thyrsoideus S.F.Blake Aster tradescantii var. thyrsoideus (A.Gray) B.Boivin

Symphyotrichum ontarionis (formerly Aster ontarionis) is a species of flowering plant in the family Asteraceae native to eastern North America. Commonly known as Ontario aster and bottomland aster, it is a perennial, herbaceous plant that may reach heights of 120 centimeters (4 feet). Each flower head has many tiny florets put together into what appear as one.

Description

Symphyotrichym ontarionis forms colonies. The plants are 20–120 centimeters (3⁄4–4 feet) tall with herbaceous stems arising singly from long thick rhizomes. The leaves are alternate and simple. The flowers, produced between July and October, have white ray florets and yellow centers composed of disk florets.

Stems

Usually, each plant has one stem arising from the rhizome, but there can be as many as three. They are straight and erect, with no hair mid-stem, becoming uniformly hairy farthest away from the base (distally). These hairs can be long and soft or coarse. Symphyotrichum ontarionis var. glabratum may have little to no hair (glabrous) on the distal stems.

Leaves

Characteristics vary among leaves on the same plant. They occur on the base, stems, and branches and become smaller the farther away from the base they grow. By the time flowers appear, the leaves at the base and on the stem have often withered or fallen.

The leaves are thin, have short hairs on the edges (margins), and come to a point. The backs usually have straight hairs all pointing in more or less the same direction, and the fronts of the leaves are generally the same, sometimes rough to the touch instead. On S. o. var. glabratum, both faces are hairless or nearly so (glabrate).

Basal (bottom) leaves are spatulate to oblanceolate-obovate, and they wither by the time the plant flowers. Their sizes vary in both length and width, measuring about 10–40 mm long by 5–10 mm wide. Their margins are wavy or saw-toothed, and their tips (apices) may be acute to rounded. Their bases narrow gradually (are attenuate). These leaves have a leafstalk (petiole) which may be clearly noticeable or very short, but the basal leaves are not sessile. The petioles have narrow wings, are fringed with hairs (ciliate) and wavy or saw-toothed, and are sheathed at the bottom.

Lower and middle stem leaves are about 20–80 mm long by 5–35 mm wide. Sizes become progressively smaller the farther they grow from the base. Stem leaves are usually withering by flowering. They are sessile or petiolate, and any petioles have narrow wings that may or may not clasp the stem. The shapes of the stem leaves vary from ovate or lance-ovate to elliptic-lanceolate or oblanceolate. Their margins are wavy or saw-toothed (sometimes coarsely), and their tips (apices) may be acute to acuminate, or short-caudate. Their bases are attenuate to cuneate.

Distal leaves, higher on the stem and on the branches with the flower heads, are sessile. They are elliptic-lanceolate to oblanceolate or lanceolate in shape. Margins are entire (smooth on the edges with no teeth or lobes) or serrulate, apices are acute to acuminate, and bases are cuneate. Sizes ranges from 6–80 mm long (or longer) by 2–25 mm wide. The more distal, the smaller they are, and this size change occurs progressively.

Flowers

Ontario aster is a late-summer and fall blooming perennial. Ample, open flower heads grow in paniculiform arrays, sometimes secund (to one side) on the upper sides of the branches (known as peduncles). These branched clusters of flowers (known as inflorescences) may be ascending, at almost a right angle (divaricate), or in long arches. The open flower heads are about 13 mm across, or up to about 16 mm with longer rays.

Flower heads have a peduncle up to 10 mm long which may be covered with fine soft hair (pilose). At the base of each flower head are from one to five bracts which look like (and technically are) small leaves that grade into the phyllaries. They are linear-lanceolate and pilose.

Involucres and phyllaries

In the Asteraceae family, at the base of the head and surrounding the flowers before opening, is a bundle of sepal-like bracts or scales called phyllaries, which together form the involucre that protects the individual flowers in the head before they open. The involucres of S. ontarionis are campanulate (bell-shaped) once the flower head opens, and are 3–5.5 mm long.

The phyllaries are appressed or spreading. The shape of the outer phyllaries is linear-obovate, and the inner phyllary shape is oblong-lanceolate to linear. They are in 4–6 (sometimes 3) unequal rows, meaning they are staggered and do not end at the same point. The margins of each phyllary are translucent, ciliate, and uneven. The phyllaries have green chlorophyllous zones that are lanceolate, with acute to acuminate and mucronulate tips. Outer phyllaries are sparsely pilose except on S. o. var. glabratum, which are glabrous. Inner phyllaries are glabrous.

Florets

The 15–26 ray florets are usually white, rarely pinkish or light purple to blue. They are 3.5–5.5 mm long, but can be as long as 8 mm, and are 0.5–1.5 mm wide.

The disk florets start out as cream or light yellow turning purple to brown when enlarged. Each has 5 lobes, and there are 12–25 florets within the disk. When the disk florets have opened, the lobes are spreading and lanceolate in shape.

Fruit

The fruits (seeds) of Symphyotrichum ontarionis are not true achenes. They are cypselae, resembling an achene but surrounded by a calyx sheath. They are gray or tan with an oblong obovoid shape and sometimes compressed. They are 1.2–2 mm long with 3–5 nerves, and are strigillose (with a few stiff, slender bristles) on their surface. They also have pappi (tufts of hairs) which are whitish to white and 3–3.5 mm long.

Chromosomes

Symphyotrichum ontarionis has a base number of x = 8 with tetraploid chromosome counts of 32 for both varieties.

Taxonomy

Along with many other species, Symphyotrichum ontarionis was formerly included in the genus Aster. However, this broad circumscription of Aster is polyphyletic and the North American asters are classified in Symphyotrichum and several other genera. The genus Symphyotrichum is sometimes called American-asters. Symphyotrichum ontarionis was created (as Symphyotrichum ontarione) with American botanist Guy L. Nesom's evaluation of Aster sensu lato in 1995.

The basionym of Symphyotrichum ontarionis is Aster ontarionis Wiegand, and it has several taxonomic synonyms. Its name with author citations is Symphyotrichum ontarionis (Wiegand) G.L.Nesom. American botanist Karl McKay Wiegand, in 1928, formally described what we know today as Symphyotrichum ontarionis. Wiegand, written Wiegand, is the standard botanical author abbreviation for Karl McKay Wiegand. Likewise, G.L.Nesom is the abbreviation for Guy L. Nesom. Wiegand's abbreviation is placed in parentheses because his authorship was retained when Nesom cited Aster ontarionis Wiegand as the basionym at the time he renamed the species.

Symphyotrichum ontarionis is classified in the subgenus Symphyotrichum, section Symphyotrichum, subsection Dumosi. It is one of the "bushy asters and relatives". The word Symphyotrichum has as its root the Greek symph, which means "coming together", and trichum, which means hair. The species name ontarionis is a Latinization of Ontario for Lake Ontario, as Wiegand stated in his description that the species was "apparently limited to the upper St. Lawrence Valley not far from Lake Ontario."

Two varieties of Symphyotrichum ontarionis are recognized:

• S. ontarionis var. ontarionis, the autonym, has leaves hairy underneath. As the autonym variety, it was automatically created when the first variety was defined.
• S. ontarionis var. glabratum (Semple) Brouillet & Bouchard, the glabrate variety, has leaves hairless or nearly so underneath.

Distribution and habitat

Symphyotrichum ontarionis occurs from Ontario and Quebec south to North Carolina and Texas. S. ontarionis var. ontarionis is found throughout most of this range, and is replaced by S. ontarionis var. glabratum in northern Ontario, Quebec, and Michigan. The species is typically found in shaded, moist soils that occur in moist forests and along stream banks.

Conservation

NatureServe lists it as Secure (G5) worldwide; Imperiled (S2) in Kansas, Vermont, and West Virginia; and, Vulnerable (S3) in Georgia.

Notes

1. Sometimes up to 20 mm
2. See Asteraceae § Flowers for more detail.
3. Outside range 10–26
4. All species in the Symphyotrichum genus have disk florets that mature or turn to a pink, purple, or light brown. This is not unique to this species.
5. There are 5 lobes on the disk florets of all species in Symphyotrichum genus.

References

1. ^ NatureServe (5 March 2021). "Symphyotrichum ontarionis Ontario Aster". explorer.natureserve.org. Arlington, Virginia. Retrieved 11 March 2021.
2. ^ POWO (2022). "Symphyotrichum ontarionis (Wiegand) G.L.Nesom". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 22 October 2022.
3. ^ Brouillet, L.; Semple, J.C.; Allen, G.A.; Chambers, K.L.; Sundberg, S.D. (2006). "Symphyotrichum ontarionis". In Flora of North America Editorial Committee (ed.). Flora of North America North of Mexico (FNA). Vol. 20. New York and Oxford: Oxford University Press. Retrieved 22 November 2020 – via eFloras.
4. Hilty, J. (2018). "Ontario Aster Symphyotrichum ontarionis". illinoiswildflowers.info. Retrieved 22 November 2020.
5. ^ 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). Vol. 20. New York and Oxford: Oxford University Press. Retrieved 22 November 2020 – via eFloras.
6. ^ Semple, J.C. (n.d.). "Symphyotrichum subsect. Dumosi Bushy Asters and Relatives". www.uwaterloo.ca. Ontario. Archived from the original on 27 May 2021. Retrieved 12 August 2021.
7. Semple, J.C. (27 April 2021). "An overview of "asters" and the Tribe Astereae". www.uwaterloo.ca. Ontario. Archived from the original on 27 May 2021. Retrieved 22 June 2021.
8. Native Plant Trust (2020). "Symphyotrichum (American-aster): Go Botany". gobotany.nativeplanttrust.org. Framingham, Massachusetts. Archived from the original on 28 November 2020. Retrieved 29 January 2021.
9. Nesom, G.L. (1995). "Review of the taxonomy of Aster sensu lato (Asteraceae: Astereae), emphasizing the New World species". Phytologia. 77 (3). Huntsville, Texas: Michael J. Warnock: 141–297. ISSN 0031-9430. Retrieved 24 December 2020 – via Biodiversity Heritage Library.
10. IPNI (2020). "Symphyotrichum ontarionis (Wiegand) G.L.Nesom". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 29 January 2021.
11. IPNI (2020). "Aster ontarionis Wiegand". International Plant Names Index (IPNI). Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; Australian National Botanic Gardens. Retrieved 29 January 2021.
12. IPNI (2020). "Wiegand, Karl McKay (1873-1942)". www.ipni.org. The Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; and, Australian National Botanic Gardens. Retrieved 29 January 2021.
13. IPNI (2020). "Nesom, Guy L. (1945-)". www.ipni.org. The Royal Botanic Gardens, Kew; Harvard University Herbaria & Libraries; and, Australian National Botanic Gardens. Retrieved 29 January 2021.
14. Turland, N.J.; Wiersema, J.H.; Barrie, F.R.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Kusber, W.-H.; Li, D.-Z.; Marhold, K.; May, T.W.; McNeill, J.; Monro, A.M.; Prado, J.; Price, M.J.; Smith, G.F., eds. (2018). CHAPTER VI: CITATION - SECTION 1: AUTHOR CITATIONS - ARTICLE 49, International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile. Vol. 159. Glashütten, Hesse, Germany: Koeltz Botanical Books. doi:10.12705/Code.2018. ISBN 978-3-946583-16-5. Retrieved 21 December 2020.
15. Semple, J.C. (17 May 2021). "Classification of Symphyotrichum in the restricted sense". www.uwaterloo.ca. Ontario. Archived from the original on 27 May 2021. Retrieved 7 July 2021.
16. Missouri Botanical Garden (n.d.). "Symphyotrichum lateriflorum - Missouri Botanical Garden Plant Finder". www.missouribotanicalgarden.org. St. Louis. Archived from the original on 17 November 2020. Retrieved 29 January 2021.
17. Wiegand, K.M. (1928). "Aster lateriflorus and some of its relatives". Rhodora. 30. Providence, Rhode Island: Preston and Rounds Co. ISSN 0035-4902. Retrieved 29 January 2021 – via Biodiversity Heritage Library.
18. Turland, N.J.; Wiersema, J.H.; Barrie, F.R.; Greuter, W.; Hawksworth, D.L.; Herendeen, P.S.; Knapp, S.; Kusber, W.-H.; Li, D.-Z.; Marhold, K.; May, T.W.; McNeill, J.; Monro, A.M.; Prado, J.; Price, M.J.; Smith, G.F., eds. (2018). CHAPTER III: NOMENCLATURE OF TAXA ACCORDING TO THEIR RANK - SECTION 3: NAMES OF GENERA AND SUBDIVISIONS OF GENERA - ARTICLE 22, International Code of Nomenclature for algae, fungi, and plants (Shenzhen Code) adopted by the Nineteenth International Botanical Congress Shenzhen, China, July 2017. Regnum Vegetabile. Vol. 159. Glashütten, Hesse, Germany: Koeltz Botanical Books. doi:10.12705/Code.2018. ISBN 978-3-946583-16-5. Retrieved 21 December 2020.
19. POWO (2022). "Symphyotrichum ontarionis var. glabratum (Semple) Brouillet & Bouchard". Plants of the World Online. Royal Botanic Gardens, Kew. Retrieved 22 October 2022.

External links

• GoBotany – Symphyotrichum ontarionis
• Ladybird Johnson Wildflower Center, wildflower.org – Symphyotrichum ontarionis
• Minnesota Wildflowers – Ontario Aster
• Ontario Wildflowers – Ontario Aster
• Symphyotrichum ontarionis var. ontarionis (Wiegand) G.L.Nesom – Online Virtual Flora of Wisconsin

• NatureServe secure species
• Symphyotrichum
• Flora of Canada
• Flora of the United States
• Plants described in 1928
• Taxa named by Karl McKay Wiegand