ASTERACEAE (COMPOSITAE)

Annual, biennial or perennial herbs, sometimes shrubs, rarely trees or vines; with or without milky latex or resin ducts. Leaves often in basal rosette; cauline leaves usually alternate, rarely opposite or whorled; usually petiolate, sometimes sessile with bases decurrent on to stems, exstipulate; leaf blades to variously lobed or divided. Individual flowers (termed Florets) small and numerous, sessile, aggregated on a receptacle surrounded by an involucre made up of 1-many series 1-5 (-15+) of bracts (termed Phyllaries or Involucral bracts) and the whole structure (Florets + Phyllaries) termed as CAPITULUM or HEAD. Phyllaries herbaceous, fully scarious or only at margins or chartaceous; involucres sometimes subtended by additional bracts, the calyculi (sing. calyculus). Receptacles usually flat to convex, sometimes conic or colmnar; paleate (bearing receptacle scales/ paleae) or epaleate (naked, lacking scales) or bearing long hairs or bristles and receptacular surface with or without scale-like ridges. Capitula homogamous (all florets bisexual OR of one sexual state: male or female) or heterogamous (florets of more than one sexual state). Homogamous capitula discoid or ligulate. Heterogamous capitula: radiate, radiant or disciform**. Individual capitula sessile or each borne on a peduncle, capitula borne singly or in usually cymiform, corymbiform, racemiform, paniculiform or spiciform arrays. Florets epigynous, bisexual, female or male (at least functionally) or sterile (neuter). Calyx often represented by Pappus of 1 or more series of scales or bristles at apex of ovary or sometimes pappus completely absent. Corolla gamopetalous, tubular, tubular-filiform, ligulate, rarely bilabiate, usually 3- or 5-toothed, rarely absent. Stamens 5, epipetalous, inserted in the corolla tube; anthers connate forming a tube around style; filaments free, rarely anthers free, dehiscence introrse, calcarate or ecalcarate, caudate or ecaudate or sometimes sagittate; apex with (rarely without) a sterile, ovate or lanceolate appendage. Carpels 2, syncarpous; ovary inferior, unilocular with a basal ovule; style distally 2-branched, style branches variously shaped with or without an apical appendage, hairs or papillae. Fruit an achene (or cypsela), with or without ribs, sometimes with distinct carpodium (basal attachment area). Pappus present or absent.

1701 genera about 23600 species

**In Radiate heads, peripheral florets (ray florets) in one or more series have corollas with zygomorphic limbs and may be pistillate, or styliferous and sterile, or neuter; the central florets (disc florets) have ± actinomorphic corollas and may be bisexual or functionally staminate. In Radiant heads, all florets have ± actinomorphic corollas and the peripheral florets usually have much enlarged corollas and may be bisexual, pistillate, or neuter; the central florets of radiant heads are usually bisexual. In Disciform heads, all florets (termed as Disc florets) have ± actinomorphic corollas, and peripheral florets in one or more series are usually pistillate and usually have relatively slender, often filiform corollas.The central florets are usually bisexual, sometimes functionally staminate.