Fl. Amer. Sept. 2: 575. 1813.
Perennials, to 200 cm (rhizomatous, rhizomes stout). Stems densely hirsute (hairs mostly antrorse, to 0.5 mm). Leaves: blades ovate to elliptic (not lobed), margins denticulate to serrate, apices acute to obtuse or acuminate, faces densely hirsute and glanddotted (glands fewer adaxially); basal 15–30 × 3–10 cm, bases attenuate; cauline petiolate, ovate to elliptic, proximal 3–25 × 1–15 cm, usually 3–5-lobed, bases truncate to cuneate or rounded. Heads (8–25) in loose, corymbiform to paniculiform arrays. Phyllaries to 1.5 cm (faces hairy and ± glanddotted). Receptacles conic to hemispheric; paleae 4–6 mm, apices acute, abaxial tips hirsute and glanddotted. Ray-florets 10–16; laminae (yellow to yellow-orange) linear to oblanceolate, 20–40 × 5–8 mm, abaxially sparsely hairy, abundantly glanddotted. Discs 10–17 × 5–15 mm. Disc-florets 200–400+; corollas yellowish green on basal 1/2, otherwise brown-purple, 3–4.2 mm; style-branches ca. 1 mm, apices acute. Cypselae 2–3.5 mm; pappi coroniform, to ca. 0.2 mm. 2n = 38.
Phenology: Flowering late summer–fall.
Habitat: Mesic to wet prairies, stream banks, and woodland openings
Elevation: 20–300 m
Ark., Conn., Ill., Ind., Iowa, Kans., Ky., La., Mass., Mich., Miss., Mo., N.Y., N.C., Okla., Tenn., Tex., Wis.
Rudbeckia subtomentosa is often cultivated as an ornamental.