Plants 30-200 cm; rhizomes long-creeping, forming clones. Stems 1-50+, erect, glabrous or densely hispid to strigose. Leaves: basal withering by flowering; proximal cauline usually withering by flowering, sessile, blades elliptic to lanceolate, 68-104 × 20-25 mm, margins sharply serrate, apices acute to attenuate, abaxial faces usually hispido-strigose (at least on main nerves), nerves sometimes prominent, abaxial glabrate; mid to distal cauline sessile, blades lanceolate, elliptic or ovate, (15-)40-75(-90) × (6-)12-22(-32) mm, largest at midstem, somewhat reduced to much reduced distally, margins coarsely to finely serrate, ciliate, indument similar to proximal or denser. Heads 50-1500 , secund, in secund-pyramidal paniculiform arrays 7-36(-50) × 9-26 cm, compact to lax, branches divergent and recurved, longest 0.8-34 cm, leafy-bracteate. Peduncles 1-1.8 mm, sparsely to densely hispido-strigillose; bracteoles linear- lanceolate to ovate. Involucres narrowly campanulate, (2-)2.5-3.5(-4.5) mm. Phyllaries in 3-4 series, strongly unequal, lanceolate to linear-lanceolate, acute to obtuse. Ray florets (4-)6-8(-12); laminae (0.9-)1-1.6(-2.3) × 0.4-0.7 mm. Disc florets (2-)4-6(-8); corollas 2-3.5(-4.5) mm, lobes (0.5-)0.7-1(-1.3) mm. Cypselae (narrowly obconic) 0.9-1.5 mm, moderately strigillose; pappi 1.8-2.5 mm. Solidago rugosa is highly variable in size, array shape, and hairiness. It is similar to members of the S. canadensis complex; it differs in not having 3-nerved leaves. The species is divided into two subspecies and five varieties that can be difficult to distinguish.
Stems 3-15(-25) dm from long creeping rhizomes, evidently spreading-hirsute (glabrous in var. sphagnophila); lvs chiefly cauline, numerous, crowded, slightly to very strongly rugose-veiny, not triple-nerved, glabrous or scabrous above, hirsute at least on the midrib and main veins beneath (except var. sphagnophila), lance-elliptic to lance-ovate or rhombic- elliptic, serrate, subsessile, not clasping, the larger ones 3.5-13 נ1.3-5 cm; infl paniculiform, with recurved-secund branches; invol 2.5-4(-5) mm, its bracts slender, not more than ca 0.6 mm wide; rays 6-11, small; disk-fls (3)4-8; achenes short-hairy; 2n=18, 36, 54. Various habitats; Nf. to Fla., w. to Mich., Mo., and Tex. (S. altissima, misapplied) Two ssp. may be distinguished, and the typical one may be divided into 3 vars., as follows:
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.