50d. Symphyotrichum lanceolatum (Willdenow) G. L. Nesom var. latifolium (Semple & Chmielewski) G. L. Nesom, Phytologia. 77: 285. 1995.
Aster lanceolatus Willdenow var. latifolius Semple & Chmielewski, Canad. J. Bot. 65: 1060, figs. 15, 16. 1987
Stems stout to slender, glabrous or hairy in lines. Leaf blades broadly oblanceolate (not much reduced in arrays), margins usually serrate. Heads 3–10+ per branch, if many, not congested on lateral branches, not subtended by foliaceous bracts. Involucres 3.9–5.5 mm. Phyllaries: outer 1.9–3.5 × 0.4–0.6 mm, inner 3–4.9 × 0.4–0.6 mm, outer 1 / 3 – 2 / 3 length of inner. Ray florets 16–33; corollas white, laminae 4.1–8.6 mm. Disc florets 13–29; corollas 3.2–5.7 mm, limbs 1.9–3.2 mm, lobes 0.4–1.1 mm. Cypselae 0.8–1.8 mm; pappi 3.1–5.3 mm. 2n = 64.
Flowering Jul–Oct. Full sun to partial shade, thickets, edges of wet deciduous woods, margins of streams, ditches; 0–800+ m; Man., Ont.; Ala., Ark., Conn., D.C., Fla., Ga., Ill., Ind., Iowa, Kans., Ky., La., Maine, Md., Mass., Mich., Minn., Miss., Mo., Nebr., N.H., N.J., N.C., N.Dak., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis.
Variety latifolium is generally more southern than var. lanceolatum. It is present in the southern Atlantic and Gulf coastal plain states where the latter is absent. In the southern states it is present inland and not on the coastal plains. The report of this variety for southern Quebec remains to be confirmed.