These can be fleshy or woody depending on the species. Some species have underground stems in the form of caudices or rhizomes. Members of the family Asteraceae generally produce taproots, but sometimes they possess fibrous root systems. Nonetheless, determining genera and species of some groups such as Hieracium is notoriously difficult (see ' damned yellow composite' for example). Asteraceae species are generally easy to distinguish from other plants because of their unique inflorescence and other shared characteristics, such as the joined anthers of the stamens. Members of the Asteraceae are mostly herbaceous plants, but some shrubs, vines, and trees (such as Lachanodes arborea) do exist. Species outside of their native ranges can be considered weedy or invasive. It is estimated that the crown group of Asteraceae evolved at least 85.9 mya (Late Cretaceous, Santonian) with a stem node age of 88–89 mya (Late Cretaceous, Coniacian).Īsteraceae is an economically important family, providing food staples, garden plants, and herbal medicines. The oldest known fossils are pollen grains from the Late Cretaceous ( Campanian to Maastrichtian) of Antarctica, dated to c. Their primary common characteristic is flower heads, technically known as capitula, consisting of sometimes hundreds of tiny individual florets enclosed by a whorl of protective involucral bracts. Most occur in hot desert and cold or hot semi-desert climates, and they are found on every continent but Antarctica. The family has a widespread distribution, from subpolar to tropical regions, in a wide variety of habitats. Most species of Asteraceae are annual, biennial, or perennial herbaceous plants, but there are also shrubs, vines, and trees. The number of species in Asteraceae is rivaled only by the Orchidaceae, and which is the larger family is unclear as the quantity of extant species in each family is unknown. Commonly referred to as the aster, daisy, composite, or sunflower family, Compositae were first described in the year 1740.

aɪ/), alternatively Compositae, consists of over 32,000 known species of flowering plants in over 1,900 genera within the order Asterales. The family Asteraceae ( / ˌ æ s t ə ˈ r eɪ s i.

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