Perennials, 30–90 cm, colonial; long-rhizomatous. Stems 1–5+, erect (light to reddish brown, straight, sometimes stout), proximally moderately to densely hispidulo-strigillose, sometimes glabrescent, distally moderately to densely hispidulo-strigillose, sometimes sparsely stipitate-glandular. Leaves (green to dark green) firm, margins entire, faces sparsely to moderately strigoso-scabrous, sometimes sparsely stipitate-glandular; basal absent at flowering, sessile, blades (3-nerved) oblanceolate to obovate, 25–40 × 12–15 mm, bases attenuate, margins entire (remotely serrate), scabrous, apices obtuse, short-mucronate; proximal cauline usually withering by flowering, sessile, blades obovate to oblanceolate, 25–80 × 5–18 mm, bases rounded or narrowly auriculate-clasping, margins distally shallowly serrate to subentire, scabrellous, apices spinulose-mucronate; distal sessile, blades lanceolate or oblanceolate to oblong-lanceolate, 5–50 × 2–10 mm, reduced distally and becoming bractlike (arrays), bases subclasping to (distally) rounded, margins scabrous, apices acute to white-mucronulate or -subspinulose, faces sometimes shiny, minutely gland-dotted. Heads (4–400) in wide to narrow, paniculiform arrays, branches ascending to widely spreading (well-developed), densely small-leaved. Peduncles ascending (secund in well-developed arrays?), 0.3–4.5 cm, densely strigoso-hirsute, sometimes sparsely stipitate-glandular, bracts dense, spreading or reflexed (rarely ascending), narrowly oblong to linear-lanceolate, mostly ca. 3 × 1 mm, spinulose, sparsely to moderately strigilloso-scabrous, sometimes sparsely minutely stipitate-glandular, grading into phyllaries. Involucres cylindro-campanulate, 6–7.6 mm. Phyllaries in 4–5 series (appressed), oblong or oblanceolate (outer) to linear-oblanceolate (innermost), unequal, bases indurate, margins hyaline, scarious, erose, ciliate or ciliolate, and/or sometimes stipitate-glandular, often reddish distally, green zones elliptic (outer) to lanceolate, apices erect, acute to acuminate, mucronulate to apiculate (inner), often tinged red-purplish, faces glabrous or glabrate. Ray florets 15–30; corollas purplish-blue to lavender, laminae 7–13 × 0.8–2 mm. Disc florets 19-25; corollas cream to pale yellow turning reddish purple, sometimes also brownish, 5.2–6 mm, tubes slightly shorter than funnelform throats, lobes lanceolate to triangular, 0.8–1.2 mm. Cypselae tan, obovoid-fusiform, slightly compressed, 1.9–2.3 mm, 4–5-nerved (golden bronze), faces sparsely strigillose to glabrescent; pappi sordid, 5–6.2 mm.
Phenology: Flowering Nov–Dec.
Habitat: Moist, sometimes peaty soils, marshes, sandhills, hammocks, flood plains, ditch banks, rocky bluffs along streams
Elevation: 0–50 m
Of conservation concern.
Symphyotrichum fontinale has been considered to be conspecific with S. patens or S. dumosum of subg. Symphyotrichum (A. Cronquist 1980). It fits well into sect. Grandiflori of subg. Virgulus.