Polymnieae

Perennial herbs without latex; leaves opposite; heads radiate, small to medium-sized; involucre campanulate to hemispheric, bracts imbricate without hyaline margins in 2–3 series; receptacle paleate; ray corollas white, limbs 3-lobed, middle lobe longer and wider than lateral lobes; disk florets yellow, tubular with five equal lobes, functionally staminate; anther api- cal appendages deltate, anther thecae pale, without spurs (ecalcarate) or tails (ecaudate); pollen echinate and spheri- cal; styles slender, branches tapering with short hairs, remainder of style glabrous, at maturity style branches not recurving; achenes dorsiventrally compressed, achene walls smooth, with phytomelanin layer; pappus absent or coroniform.

Diagnostic Features

Combination of opposite leaves; paleate receptacles; functionally staminate disc florets; pale anthers; and uncompressed smooth achenes.

Geographic distribution

Eastern North America.