Perennials, 25–100 cm. Stems (branched distal to midstems) glabrous or glabrate, not glaucous. Leaves deflexed to erect; blades 1–5-nerved, linear, 24–70 × 1–3 mm (to 6 mm wide in some Maine and Nova Scotia populations), lengths 7.7–42.2 times widths, abruptly reduced distally, lax-to firm-herbaceous, apices obtuse to long-acuminate, faces abundantly and prominently gland-dotted (34–86 dots per mm 2 ), glabrous, glabrate, or scabro-hirtellous on midnerves. Heads pedunculate or glomerulate, usually in flat-topped or rounded arrays 10–40% of plant heights (often with multiple layers, proximal branches 0.5–1 times array heights). Involucres campanulate to turbinate, 3–4.7(–5.3) mm . Phyllaries usually green-tipped, outer ovate, inner oblong-linear, apices obtuse to acute. Ray florets 7–17(–25). Disc florets 3–22; corollas 3.3–4.8 mm. 2n = 18.
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