4d. Symphyotrichum subulatum (Michaux) G. L. Nesom var. subulatum
Aster subulatus Michaux var. obtusifolius Fernald
Plants 30–120(–150) cm. Stems simple. Heads (10–)30–100(–150), in elongate, pyramidal, much branched arrays. Involucres (5–) 6–7(–8.2) mm. Phyllaries 20–30, subulate to lanceolate, narrow, green zones narrowly to broadly lanceolate, extending phyllary length. Ray florets 16–30 in 2 series; laminae white (drying white or lavender), (1.3–)1.5–2.6(–3.1) × 0.2–0.5 mm, shorter to slightly longer than pappi, drying in 0–1 coil (apices often deeply lobed). Disc florets 4–10(–13); corollas 3.8–4.6(–4.9) mm. Cypselae (1.2–)1.5–2.5 mm; pappi (3.5–)4–5.5 mm. 2n = 10.
Flowering midsummer–autumn(–winter). Salt marshes, brackish marshes, tidal marshes, salted highways; 0 (100–300 inland) m; N.B., Ont.; Ala., Ark., Conn., Del., Fla., Ga., Ill., Ind., La., Maine, Md., Mass., Mich., Miss., Nebr., N.H., N.J., N.Y., N.C., Ohio, Pa., R.I., S.C., Tex., Va.; introduced in Asia, Africa.
Variety subulatum is disjunct in northern New Brunswick. It is apparently introduced around salt mines and other salted habitats in Ontario, Michigan, and Ohio.