Skr. Naturhist. Selsk. 2(2): 29, plate 4. 1793.
Leaf blades 3–15 × 0.5–4 cm. Involucres 1–4 cm diam. Phyllaries spreading to reflexed, green, linear to lanceolate, herbaceous. Ray laminae spreading, eventually reflexed, elliptic to obovate, 12–30 × 7–15 mm, abaxially hirsute. Disc corollas 2.8–3.5 mm. Cypselae: each face 4–5-striate and minutely cross-rugose, glabrous; pappi 0 (cypselae each with ring of tan tissue at apex, ca. 0.1 mm). 2n = 32.
Phenology: Flowering late spring–summer.
Habitat: Open sites, moist soils
Elevation: 0–400 m
Ala., Ark., Fla., Ga., Ill., Kans., La., Miss., Mo., N.Mex., N.Dak., Okla., S.C., Tex.
Rudbeckia amplexicaulis grows mainly in the Gulf coastal plain and Mississippi Embayment. It may be adventive elsewhere. It is used in “native” meadow and roadside plantings and has become a problem in some agricultural crops.