XVI International Botanical Congess

Asterids have been recognized as a group characterized by sympetalous corollas ever since the 18th century. Before the era of molecular systematics the group included taxa now classified in the Asterales, Dipsacales, Ericales, Gentianales, Lamiales, and Solanales. With molecular data it became evident that the asterids should include also the Apiales, Aquifoliales, Cornales, Garryales, and an extended Ericales, as circumscribed in the APG-classification. If species number is a measurement of evolutionary success the asterids are a successful group comprising ca 86,000 species or 1/3 of the flowering plants. Orders are not always comparable units and many sister pairs are still unclear, but, there are well supported sister pairs. In these, there are examples where the species number differs. There are indications that simple morphological traits are responsible for these differences.