Perennials, 15-60(-100) cm (taproots relatively massive; caudices seldom branched). Stems erect (or bending erect from bases), branched mostly from bases. Leaves basal and cauline; alternate; usually petiolate (basal), sometimes sessile; blades (usually pinnately nerved, basal larger than cauline) ± deltate, elliptic-ovate, lanceolate, lance-elliptic, lance-linear, or oblong-ovate, bases truncate to cuneate, margins usually entire, rarely dentate to serrate (sometimes ciliate), faces glabrous or hairy (sometimes gland-dotted or finely stipitate-glandular). Heads radiate, borne singly or 2-5(-8+) in ± corymbiform to racemiform arrays. Involucres hemispheric to campanulate or turbinate, 12-60+ mm diam. Phyllaries persistent, 12-36(-48) in 2-3+ series (subequal to unequal, outer sometimes foliaceous, much larger than inner). Receptacles flat to convex, paleate (paleae conduplicate, at least bases, papery). Ray florets 5-25+, pistillate, fertile; corollas mostly yellow (cream to white in W. helianthoides). Disc florets 35-150+, bisexual, fertile; corollas yellow, tubes much shorter than cylindric throats; lobes 5, ± deltate to lanceolate (style branches stigmatic in 2 barely distinct lines, appendages ± filiform). Cypselae ± prismatic, weakly 3-4-angled (faces glabrous or hairy); pappi 0, or persistent, coroniform (usually lacerate) or of 1-4+ ovate to subulate, erose to lacerate (often basally connate) scales. x = 19.
Some species formerly included in Wyethia are here treated in Agnorhiza and Scabrethia. Balsamorhiza is closely related to Wyethia.
This project was made possible in part by the Institute of Museum and Library Services [MG-70-19-0057-19].