117. Erigeron elatus (Hooker) Greene, Pittonia. 3: 164. 1897.
Swamp fleabane, vergerette élevée
Erigeron alpinus Linnaeus var. elatus Hooker, Fl. Bor.-Amer. 2: 18. 1834; E. acris Linnaeus var. arcuans Fernald; E. acris var. elatus (Hooker) Cronquist; E. elatus var. oligocephalus (Fernald & Wiegand) Fernald; Trimorpha elata (Hooker) G. L. Nesom
Biennials or short-lived perennials, (6–)10–40(–50) cm; fibrous-rooted, caudices simple or branched, or rhizomes. Stems erect, sparsely to moderately strigose or loosely strigoso-villous or glabrate, often minutely glandular near heads. Leaves basal (persistent) and cauline; basal blades oblanceolate to spatulate, 20–80 × 2–6 mm, cauline gradually reduced distally, margins usually entire, rarely dentate, glabrous or sparsely villoso-hirsute, distal sometimes also glandular. Heads 1–5(–8) in corymbiform arrays (on straight, spreading peduncles). Involucres 5–11 × 8–12 mm. Phyllaries in 2–3 series (inner apices attenuate to caudate), sparsely hirsute to villoso-hirsute, eglandular or sparsely minutely glandular only at tips. Ray (pistillate) florets in 2 series: outer 45–60, corollas white to pink, 5–7 mm, laminae (filiform) erect, not coiling or reflexing; inner far fewer than outer, elaminate. Disc corollas 4.2–6.2 mm. Cypselae 1.6–1.8 mm, 2-nerved, faces sparsely strigose; pappi: outer of setae, inner of 24–35 (accrescent) bristles. 2n = 36.
Flowering (Jun–)Jul–Aug. Floodplain meadows, pond edges, open boggy woods, tundra; 200–2000 m; Alta., B.C., Man., Nfld. and Labr., N.W.T., Ont., Que., Sask., Yukon; Alaska, Wash.