COMPOSITAE
General description:- A very large cosmopolitan family of annual, biennial and perennial herbs, shrubs and, less commonly, trees or climbers. Leaves are simple or divided, alternate or opposite, and stipules are absent.
Characteristics:- The apparent flower is typically a capitulum composed of many small florets crowded on a common receptacle and surrounded by an involucre of bracts. Capitula may contain ray florets, disc florets, ligulate florets, or combinations of these.
Flowers:- Florets usually have a 5-lobed sympetalous corolla. Stamens are normally 5, with the anthers united into a tube around the style. The ovary is inferior, formed from 2 carpels and containing a single ovule. The calyx is modified into a pappus of hairs, bristles or scales, or is absent.
Fruit and seeds:- Fruit a dry, indehiscent, one-seeded cypsela, often bearing a pappus that assists dispersal.
Recognition:- Recognised principally by the capitulum: numerous florets are condensed into a flower head surrounded by involucral bracts. The individual florets and the structure of the involucre, receptacle, pappus and cypsela provide important diagnostic characters.
Genera relevant to catalogue:- Achillea and numerous further genera to be added as the family catalogue progresses.
Taxonomic note:- Compositae and Asteraceae are both accepted family names under botanical nomenclature; current Kew/APG classification uses Asteraceae.
Catalogue note:- This is a large family and will be developed progressively by genus and species.