Perennials. Stems simple or branched, 5–15 dm, white-puberulent. Leaves: petiole 8–18 mm; blade lanceolate, 50–105 x 30–40 mm, margins pinnatifid and serrate, rarely serrate and not pinnatifid, surfaces puberulent. Bracts leaflike, 15–22 x 3–7 mm, margins serrate to weakly pinnatifid at base. Pedicels 4–11 mm, puberulent. Flowers: calyx puberulent, tube campanulate, 6–10 mm, lobes linear to lanceolate, 3–12 x 1–4 mm, margins entire; corolla tube 30–40 mm, glabrous, lobes 7–11 x 10–16 mm; filaments 13–27 mm, ciliate; style 29–35 mm. Capsules pyriform, 10–16 x 8–12 mm, glabrous.
Phenology: Flowering Jul–Oct.
Habitat: Maple, pine, and oak woodlands, roadsides.
Elevation: 0–400 m.
Ont., Ark., Ill., Ind., Iowa, Kans., La., Mo., Okla., Tex., Wis.
J. C. McFeeley and E. P. Roberts (1974) documented Aureolaria grandiflora, typically a parasite of oaks, parasitizing Juniperus virginiana in addition to oak species. F. W. Pennell (1935) recognized four infraspecific taxa within A. grandiflora, differentiated on subtle characteristics (for example, bract margins serrate versus more deeply cut, leaf blade margins more versus less pinnatifid). Additionally, he recognized these infraspecific taxa at both the varietal and subspecific ranks (at different times). No infraspecific taxa are recognized here.
There is a historic record of Aureolaria grandiflora from Houston County, Minnesota, collected in 1899.