Arranged alphabetically under families, this work lists all species and intraspecific taxa. The volume contains full checklists of important, mainly temperate, genera such as Alnus (alders), Betula (birches), Carpinus (hornbeams), Corylus (hazels), Castanea (chestnuts), Fagus (northern beeches), Nothofagus (southern beeches), and Quercus (oaks). 531 species are accounted for in the last-named genus, its first complete listing since 1954. As well as describing each family and genus, it covers life form and distribution. References to important related literature and line illustrations augment these descriptions. Synonyms are extensively listed throughout, and the introduction provides a succinct summary of the current state of taxonomic knowledge.