Herbs or shrubs without latex; leaves opposite or alternate; heads radiate or discoid, 2–15 cm wide; involucre cylindric to hemispheric, bracts usu- ally in two or more continuous series, outermost green, linear to lanceolate, striations dark green or brownish- black, inner with brownish-orange striations and scarious margins, usually ovate; receptacle with brownish-orange striated paleae, flat to conical; corollas mostly yellow or white; ray florets neuter or pistillate and then either ster- ile or fertile; disc corollas with (4–)5 lobes of equal size; anthers brown to black, apical appendage ovate, thecae without spurs (ecalcarate) and short-tailed (caudate); pol- len radially symmetrical, isopolar, spherical, echinate and tricolporate; style undivided or shortly cleft to bifurcate, branches conic with short papillae on the outer surface, recurved at maturity, apex penicellate or truncate with fringes of papillae; achenes flat to quadrangular, rarely narrowed toward the apex and beaked; pappus of 2–15 smooth, antrorsely or retrorsely barbed bristles or short awns, rarely absent.

Diagnostic Features

Outer phyllaries differentiated from inner in color and shape, inner phyllaries with or- ange-brown striations (resin ducts); paleae with brown- ish-orange striations; and achenes flat obcompressed to quadrangular.

Geographic distribution

Centered in North and South America.