Annuals, biennials, perennials, subshrubs, shrubs, vines, or trees. Roots usually taproots, sometimes fibrous. Stems usually erect, sometimes prostrate to ascending (underground stems sometimes woody caudices or rhizomes, sometimes fleshy). Leaves usually alternate or opposite, sometimes in basal rosettes, rarely in whorls; rarely stipulate, usually petiolate, sometimes sessile, sometimes with bases decurrent onto stems; blades usually simple (margins sometimes 1-2+ times pinnatifid or palmatifid), rarely compound. Inflorescences indeterminate heads (also called capitula); each head usually comprising a surrounding involucre of phyllaries (involucral bracts), a receptacle, and (1-)5-300+ florets; individual heads sessile or each borne on a peduncle; heads borne singly or in usually determinate, rarely indeterminate, arrays (cymiform, corymbiform, racemiform, spiciform, etc.); involucres sometimes subtended by calyculi (sing. calyculus); phyllaries borne in 1-5(-15+) series proximal to (i.e., outside of or abaxial to) the florets; receptacles usually flat to convex, sometimes conic or columnar, either paleate (bearing paleae or receptacular bracts that individually subtend some or all of the florets) or epaleate (lacking paleae); epaleate receptacles sometimes bristly or hairy or bearing subulate enations among the florets. Florets bisexual, pistillate, functionally staminate, or neuter (also called neutral); sepals highly modifed (instead of ordinary sepals, each ovary usually bears a pappus of bristles, awns, and/or scales, sometimes in combination within a single pappus); petals connate, corollas (3-)5-merous, ± actinomorphic or zygomorphic (one or both kinds in a single head, see descriptions of radiate, discoid, liguliflorous, disciform, and radiant following); stamens (4-)5, alternate with corolla lobes, filaments inserted on corollas, usually distinct, anthers introrse, usually connate and forming tubes around styles (rarely filaments connate and anthers distinct; e.g., Heliantheae, Ambrosiinae); ovaries inferior, 2-carpellate, and 1-locular with 1 basally attached, anatropous ovule; styles 1 in each bisexual, functionally staminate, or pistillate floret; each style usually ringed at base by a nectary, distally 2-branched with stigmatic papillae borne on adaxial face of each branch in 2 separate or contiguous lines or in 1 continuous band (