49. Solidago ulmifolia Muhlenberg ex Willdenow, Sp. Pl. 3: 2060. 1803.
Aster ulmifolius (Muhlenberg ex Willdenow) Kuntze
Plants 40–120 cm; caudices branching, woody. Stems usually 1, erect, glabrous, sparsely hairy in arrays. Leaves: basal when present similar to proximal cauline; proximal cauline often withering by flowering, tapering (sometimes rather abruptly) to short, winged petioles, blades ovate-lanceolate, 60–100(–150) × 30–40(–50) mm, thin, margins coarsely serrate, apices acute, abaxial faces hirsute on main nerves, adaxial sparsely hirsute to somewhat scabrous; mid to distal cauline subsessile to sessile, blades lanceolate, 20–50 × 5–20 mm, gradually reduced distally, margins entire. Heads 20–150, secund, in open paniculiform arrays, proximal branches elongate and widely divergent, sometimes pyramidal-secund with proximal branches short and recurved-secund. Peduncles 1.7–2 mm, sparsely to moderately short hispido-strigose, bracteoles 2–7, ovate, grading into phyllaries. Involucres 3–4 mm. Phyllaries (16–18) in 2–3 series, unequal; outer ovate, acute, inner linear-lanceolate, obtuse to acute. Ray florets 3–6; laminae 1–2 × 0.5–1 mm. Disc florets 4–7; corollas 2.7–3 mm, lobes 0.5–1.1 mm. Cypselae 1–1.6 mm, finely hairy; pappi ± 2.5 mm.
Varieties 2 (2 in the flora): North America.
Solidago helleri is possibly a hybrid of S. ulmifolia with S. delicatula.