<P>This fourth edition of <EM>Plant Systematics </EM>is completely revised and updated. It incorporates the updated International Code of Nomenclature for Algae, Fungi and Plants (Shenzhen Code, 2018), the new version of PhyloCode (Beta version of Phylocode 5, 2014), APweb version 14 (September, 2018), revised Angiosperm Phylogeny Group classification (APG IV, 2016), new Pteridophyte Phylogeny Group Classification (PPG I, 2016), besides the updates since the publication of third edition.</P><br/><br/><P>The book is a blend of classical fundamental aspects and recent developments, especially in the field of molecular systematics, cladistics and computer identification. Special attention has been given to information on botanical nomenclature, identification, molecular systematics and phylogeny of angiosperms. The complicated concepts of phylogeny, taxometrics and cladistics have been explained with a view to providing a comparison between these diverse but interactive fields of study. A