Tradescant’s Aster, Shore Aster, aster de Tradescant
Symphyotrichum tradescantii (L.) Nesom occurs scattered along damp, rocky and gravelly shores, silt- or loam-filled cracks in rocky rapids of streams or along freshwater estuaries in Newfoundland, Québec, and New Brunswick in Canada and from Maine to New York and northern New Jersey in the US (Brouillet et al. 2006; FNA). Rays are white; disc florets are pale yellow turning purplish with age, corolla lobes are shorter than in Sy. lateriflorum. Colonial dams on rivers likely eliminated many populations in the southern portion of the range long ago.
Semple et al. (2024) summarized the published chromosome counts for S. tradescanti and presented a cytogeography of all counts. Diploids 2n=16 are more common than tetraploids 2n=32 and all counts come from more northern populations.
Brouillet, L., J.C. Semple, G.A. Allen, K. Chambers and S. Sundburg. 2006. Symphyotrichum Nees. pp. 465-539. In Flora North America Editorial Committee, eds. Flora of North America. Vol. 20. Asteraceae, Part 2. Astereae and Senecioneae. Oxford University Press, New York.
Semple, J.C., J.G. Chmielewski, A. Bouchard, and L. Brouillet. 2024. The cytogeography Symphyotrichum lateriflorum, S. ontarionis, S. racemosum, and S. tradescantii (Asteraceae: Astereae). Phytoneuron 2024-68: 1–20.
Revised 11 Novembeer 2024 by J.C. Semple
© 2024 J.C. Semple, including all photographs unless otherwise indicated