J. Acad. Nat. Sci. Philadelphia 7: 40, plate 5. 1834.
Plants 25–40(–80) cm. Basal leaves: blades (light green) lance-elliptic to elliptic-ovate, (10–)20–30+ cm, margins usually entire, sometimes denticulate, ± ciliolate, faces sparsely pilose to pilosulous (usually minutely gland-dotted or stipitate-glandular as well); cauline leaves similar, smaller distally (petiolate or sessile). Heads borne singly. Involucres ± hemispheric, (12–)20–30(–40) mm diam. Phyllaries 36–48, subequal, herbaceous, margins villous-ciliate, faces glabrous or glabrate; outer 18–25 mm (not surpassing discs). Ray florets 13–25; laminae (cream to white) 25–45 mm. Cypselae 9–11 mm, strigillose distally and on margins.
Phenology: Flowering May–Jul.
Habitat: Meadows, other damp to wet sites, openings in pine forests
Elevation: 40–2600 m
Idaho, Mont., Nev., Oreg., Wyo.
Hybrids between Wyethia helianthoides and W. amplexicaulis are infrequent where the species are in contact; no introgression has been noted. The hybrids have been called Wyethia ×cusickii Piper; they usually bloom later than W. helianthoides and earlier than W. amplexicaulis.