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Symphyotrichum firmumÌý(Nees) G. L. Nesom is a little known species hiding amongst individuals ofÌýSy. puniceumÌýin eastern North America (Brouillet et al. 2006;Ìý).Ìý The species has been treated as a synonym ofÌýSy. puniceumÌý(e.g. Semple et al. 2002; 3rd ed. of the Asters of Ontario), although the morphological study by Warners & Loughlin (1999) presented strong evidence thatÌýAster firmusÌýNees was distinct in multiple ways from plants ofÌýA. puniceumÌýL. in local mixed populations in Michigan.Ìý The problem is that the differences are not absolute, e.g. 1) lighter colored and even white rayed S. puniceum are occasionally encountered, 2) while mostly hairless, some individuals ofÌýSy. firmumÌýcan have hairy stems, but the hairs tend to be in lines rather than more evenly dispersed as inÌýSy. puniceum, 3) the thinner elongated rhizomes ofÌýSy. firmumÌýare readily distinct from the thicker short branched rootstocks ofÌýSy. puniceumÌýbut most herbarium collections of both species lack lower stems and root systems.

Key toÌýSymphyotrichum firmumÌýandÌýSymphyotrichum puniceumÌý(modified from key ofÌýWarners & Loughlin 1999)

Stems glabrous, occasionally hispidulous in lines; abaxial stem leaf mid-vein glabrous; capitulescence dense, leafy; heads with white to pale lavender ray florets; shoots arising singly from elongate rhizomes ......ÌýSymphyotrichum firmum

Stems densely hispid pubescent, usually purplish; abaxial stem leaf midvein moderately to densely pubescent; inflorescence widely spreading and heads with lavender to purple ray florets; shoots often found in clumps of 2–6 arising from a persistent stout caudexÌý ...ÌýSymphyotrichum puniceum

All images were taken of a single shoot growing in a swampy woods in Erbsville, Ontario in 2005.Ìý These were taken on a short local field trip to find a more glabrous individual of "Sy. puniceum" in a population that included hairy typicalÌýSy. puniceum; the plant readily keyed out toÌýSy. firmum.Ìý The full distribution ofÌýSy. firmumÌýis yet to be determined and no range map is presented here.

Warners, D. P. and D. C. Laughlin. 1999. Evidence for a species-level distinction of two co-occurring asters:ÌýAster puniceusÌýL. andÌýAster firmusÌýNees. Michigan Bot. 38: 19–31.

Brouillet, L., J.C. Semple, G.A. Allen,Ìý K. Chambers and S. Sundburg. 2006.ÌýÌýSymphyotrichumÌýNees. 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.

Last revised 9 May 2025 by J.C. Semple

© 2025 J.C. Semple, including all photographs unless otherwise indicated