214d.2. Symphyotrichum Nees (subg. Symphyotrichum ) sect.
Perennials; rhizomatous. Stems usually simple, sometimes ± branched. Heads radiate. Ray florets fewer than disc florets, in 1 series (corollas conspicuous). Disc corollas ± ampliate, lobes usually erect, sometimes spreading or reflexed. Pappi shorter than to equaling disc florets at flowering. x = 8.
Species 39+ (36 in the flora): North America, Mexico; widely introduced worldwide through ornamental horticulture.
Subsections have been recognized within sect. Symphyotrichum. They are not treated formally here. Subsectional phylogeny is mostly unresolved. Lists of species (from the flora area) within each subsection are provided here as a rough guide to relationships.
Subsection Heterophylli (Nees) Semple: Symphyotrichum cordifolium, S. ciliolatum, S. drummondii, S. anomalum, S. shortii, S. undulatum, S. urophyllum, S. oolentangiense, S. laeve, S. retroflexum.
Subsection Porteriana (Rydberg) G. L. Nesom: Symphyotrichum depauperatum, S. parviceps, S. pilosum, S. porteri, S. priceae.