187m.3. Asteraceae Martinov (tribe Heliantheae) subtribe Polymniinae H. Robinson, Phytologia. 41: 43. 1978.
Annuals or perennials, mostly 50–150+ cm (often rhizomatous). Leaves all or mostly cauline; opposite; petiolate; blades (pinnately nerved) deltate or rounded-rhombic to cordate or ovate, often raggedly pinnately lobed, ultimate margins coarsely toothed to denticulate or entire, faces pilose or pilosulous to hirtellous, or glabrate, or glabrous, usually gland-dotted and/or stipitate-glandular. Heads usually radiate (rarely, laminae reduced, heads technically ± disciform), (2–5+) in loose to congested, corymbiform arrays. Calyculi 0. Involucres hemispheric. Phyllaries persistent, 6–21+ in 2 series (distinct, outer 2–6 ovate to linear, ± herbaceous, inner ovate to lanceolate, subequal to or shorter than outer, more scarious, similar to paleae). Receptacles flat to convex, paleate (paleae obovate to oblanceolate or spatulate, herbaceous to scarious). Ray florets 2–6, pistillate, fertile; corollas pale yellowish to whitish. Disc florets 12–30+, functionally staminate; corollas pale yellow, tubes shorter than abruptly dilated throats, lobes 5, deltate to lance-ovate; anther thecae pale; stigmatic papillae 0. Cypselae plumply pyriform, ± obcompressed, 3–6-angled or -ribbed, finely striate between ribs, sparsely hirtellous or glabrate; pappi 0.
Genus 1, species 3 (3 species in the flora): c, e North America.
Traditionally, Polymnia has been included in Melampodiinae. It was treated at tribal rank, as Polymnieae (H. Robinson) Panero, by J. L. Panero and V. A. Funk (2002).