In this volume, the ninth of the series, treatments are offered for 52 families containing 432 genera belonging to 13 eudicot orders, many of which have recently been newly designed; four families remain unassigned to order. Emphasis is on the early-diverging eudicots and basal core eudicots the phylogenetic relationships and diversification of which have recently been in focus and are critically discussed. Systematically relevant information includes descriptions of families and genera, keys to the genera, and references to recent revisions. Introductions to the families provide convenient, in-depth overviews of key aspects of systematics. The wealth and precision of information contained in this volume will make it an important source of reference for both the scholar and the practitioner in the fields of pure and applied plant sciences.