11 - Asterids

Summary

Floral diagrams are presented for thirty-six families out of nine orders of SupperAsteridae. Asterids represent the pinacle in Pentapetalae floral evolution, expressing a strong synorganization between whorls and the stabilization of a tetracyclic Bauplan with five sepals, five petals, a single whorl of stamens (haplostemony) and two carpels. The lower Asterids share characters of basal Pentapetalae and rosids and present all characteristics of a transition to euasterids. Diferent trends are higlighted in lamiids and campanulids. The development of a stamen-petal tube emerges in the basal Asterids and is prominent in the lamiids in association with median monosymmetry. An important evolutionary trend representing the sterilisation of stamens in Lamiales is shown through floral diagrams. In Campanulids there is a shift towards the reduction of the stamen-petal tube as well as the reduction of the calyx linked with an inferior ovary and a lower number of ovules.