Asteraceae

Herbs, shrubs, rarely climbers; some with latex. Leaves usually alternate, sometimes opposite, often basal, simple dissected or compound; stipules usually absent. Inflorescence a head, solitary on a scape or several together in compound inflorescences (corymbs etc.) or sometimes the heads aggregated into compound heads; each head surrounded by an involucre of 1–several rows of bracts; involucre green or coloured, chaffy, papery or fleshy, sometimes with spines. Florets bisexual or unisexual (the plants then usually monoecious); each flower sometimes subtended by a bract. Calyx represented by a pappus of fine bristles, hairs, scales, barbs, thorns, or spines; or absent. Corolla segments 5, either regular and connate into a tube (tubular florets or if very slender, filiform florets); or irregular and connate into a very short basal tube terminating in a unilateral often strap-shaped limb 3–5-lobed at the apex or entire (ligulate florets); or rarely 2-lipped (e.g Podolepis). Within a single head, florets may be: (1) all tubular); (2) tubular and filiform; (3) tubular and ligulate; (4) all ligulate; the former at the centre are called disc florets, the latter at the periphery are called ray florets or rays, and are often female or sterile by the abortion of the styles. Stamens 5, epipetalous, alternating with the corolla lobes; anthers linear, with 2 pollen sacs, connate around the style, rarely free. Ovary inferior, 2-carpellary, 1-locular; ovule solitary, basal; style usually 2-fid with 2 stigmas. Fruit a cypsela surmounted by the pappus or pappus absent. c. 1500 gen., cosmop.