Asteraceae - Sunflower family

Herbs, suffrutices, shrubs or (rarely) climbers or trees. Leaves alternate, less often opposite. Stipules 0, but false stipules occur in a few species (for example: Vernonia myriantha and Senecio deltoideus) . Flowers small (florets), aggregated into heads (capitula) and simulating single larger flowers and surrounded by a calyx-like involucre of one or more series of bracts (phyllaries). Receptacle of the head expanded, with or without receptacular scales or bristles each subtending a floret. Florets all similar sexually (head homogamous) or central and marginal florets differing (head heterogamous) and then the central florets usually bisexual or rarely male, the outer female or rarely neuter. Calyx never typically herbaceous but represented by a pappus of numerous simple or feathery (plumose) hairs, or a smaller number of membranous scales, teeth or bristles, or by a continuous membranous ring; sometimes 0.

Corolla composed of (3-)5 united petals fused into a tube below and with a distal limb consisting of either: (1) 5 actinomorphic lobes or teeth (tubular florets); or (2) a unilateral strap-shaped limb (ray) 0-3(-4)-dentate at the apex; or (3) a unilateral strap-shaped limb (ligule), 5-dentate at the apex.

Stamens 5, borne on the corolla-tube; anthers usually fused into a cylinder around the style. Ovary inferior, 1-celled, with 1 basal ovule; style single below but branching above into 2 stigmatic arms. Fruit an achene, crowned by the pappus, sometimes with a slender beak interposed between them.

Worldwide: 1,528 genera and 22,750 species, cosmopolitan, excluding Antarctica.

Botswana: 87 genera and 188 taxa.