Sp. Pl. 2: 880. 1753.
Plants 30–150 cm; caudices branching, woody. Stems 1–10+, erect, stout, hairy. Leaves: basal and proximal cauline usually present at flowering, abruptly narrowed to long-petioles, blades ovate to rhombic, 80–200 × 24–50 mm, firm, flat, margins entire to crenate, sometimes undulate, apices obtuse to acute, faces densely hairy; mid to distal cauline sessile, blades ovate, 30–50 × 15–17 mm, stiff, greatly reduced distally, margins entire or finely serrate, sometimes undulate, apices acute to obtuse. Heads 9–190, in corymbiform arrays, compact or branches long and spreading, densely hairy throughout. Peduncles 3–15 mm, strigillose-canescent, bracteoles 1–3, linear-lanceolate. Involucres campanulate, 6–8 mm. Phyllaries in 3–4 series, unequal, oblong, conspicuously striate (3–5 pronounced nerves), obtuse. Ray-florets 6–13; laminae 1.4–5.4 × 1.2–1.9 mm. Disc-florets 14–35; corollas 4.3–6.1 mm, lobes 0.6–1.1 mm. Cypselae (obconic) 0.8–1.7 mm (ribbed), glabrous or strigillose apically; pappi 3–4 mm.
Alta., Man., Ont., Sask., Ala., Ark., Colo., Conn., Del., Ga., Ill., Ind., Iowa, Kans., Ky., La., Mass., Md., Mich., Miss., Mo., Mont., N.C., N.Dak., N.J., N.Mex., N.Y., Nebr., Ohio, Okla., Pa., R.I., S.C., S.Dak., Tenn., Tex., Va., W.Va., Wis., Wyo.
Subspecies 3 (3 in the flora).
Solidago rigida is divided into three subspecies with distinct morphologies and partially overlapping ranges. Intermediates occur between the subspecies in areas of sympatry.
|1||Outer phyllaries glabrous; leaves and stems glabrous or ± hispid||Solidago rigida subsp. glabrata|
|1||Outer phyllaries strigillose; leaves and stems moderately to densely hispid or strigose||> 2|
|2||Inner phyllaries glabrate to sparsely strigillose, oblong and rounded; plants robust (60–150 cm); arrays loose, open; leaves and stems coarsely hispid (fewer than 50 hairs/mm 2)||Solidago rigida subsp. rigida|
|2||Inner phyllaries conspicuously strigillose, often linear; plants usually short (30–70 cm), sometimes taller; arrays compact; leaves and stems finely and densely hispido-strigose (more than 50 hairs/mm 2)||Solidago rigida subsp. humilis|