Symphyotrichum subg. Symphyotrichum
Annuals or perennials, eglandular; usually rhizomatous, sometimes taprooted. Stems usually not brittle at maturity, usually proximally glabrous or glabrate and distally hairy in lines, sometimes ± uniformly hairy, sometimes glabrous distally. Leaves: basal usually withering by flowering, usually petiolate, sometimes sessile or subsessile, blades 1-nerved, spatulate to oblanceolate, elliptic, or ovate to cordate, margins coarsely serrate to crenate or entire; cauline petiolate or sessile, blades widely ovate to linear, bases cordate or subcordate, rounded, cuneate, or attenuate, sometimes auriculate and ± clasping. Heads radiate or disciform. Phyllaries strongly unequal to subequal, outer sometimes ± foliaceous, green zones usually diamond-shaped to lanceolate, apices sometimes foliaceous. Ray (or pistillate) florets usually (6–)7–50(–60) in 1 series and laminae (3–)5–18(–21) × 0.8–2.8 mm, sometimes 14–110+ in 2–5+ series (sect. Conyzopsis) and laminae 4.5–5 × 0.1–0.2 mm or reduced to tubes. Disc corollas ± ampliate, throats usually ± narrowly funnelform, sometimes cylindric or funnelform-campanulate, lobes usually erect, sometimes spreading, recurved, or reflexed. Cypselae cylindric to obovoid or oblong, sometimes ± compressed, 2–6-nerved, glabrous or ± strigillose. x = 7, 8.
North America, Mexico, Eurasia.
Species ca. 58 (51 in the flora).
Subgenus Symphyotrichum has been divided into three sections: sect. Conyzopsis (x = 7), sect. Symphyotrichum (including sect. Turbinelli) (x = 8), and sect. Occidentales (x = 8). Relationships among sections remain unresolved, and it is uncertain whether sect. Symphyotrichum, for instance, is monophyletic as defined here or elsewhere (e.g., G. L. Nesom 1994b).