3. Euthamia gymnospermoides Greene, Pittonia. 5: 75. 1902.
Great Plains goldentop
Euthamia camporum Greene; E. chrysothamnoides Greene; E. glutinosa Rydberg; E. pulverulenta Greene; Solidago gymnospermoides (Greene) Fernald var. callosa Harris; S. texensis Friesner
Perennials or subshrubs, 40–150 cm. Stems (simple or branched) glabrous or with scabrous lines, not glaucous. Leaves usually ascending; blades (1–)3- or -5-nerved, linear to lanceolate, 40–100(–120) × 1.4–4(–8) mm, lengths 12–49 time widths, gradually reduced distally, firm-herbaceous, margins scabrous, apices acuminate, faces abundantly and prominently gland-dotted (29–49 dots per mm²), glabrous or midveins with hairs. Heads (some or all) pedunculate (rarely all glomerate), usually in flat-topped to slightly rounded, arrays (25–)35–60% of plant heights. Involucres obconic, (4–)4.5–6.2 mm. Phyllaries usually green-tipped, outer ovate, inner linear-oblong, apices obtuse to acute (± strongly resinous). Ray florets 9–13(–16). Disc florets 3–9; corollas (3–)3.3–4.8 mm. 2n = 36, 54.
Flowering Aug–Sep. Open, dry to moist, sandy areas; 0–200 m; Ont.; Ark., Colo., Del., Fla., Ill., Ind., Iowa, Kans., La., Minn., Mo., Nebr., N.C., Okla., S.C., S.Dak., Tex., Va., Wis.
Some plants from the southern Great Lakes area with tendencies to shorter involucres and narrower leaves, called Euthamia gymnospermoides by H. A. Gleason and A. Cronquist (1991) and D. J. Sieren (1981), are better included in E. caroliniana.