The term geme, the basic gene complement of an individual, is almost synymous with the chromosome complement of both nucleus and organelles. Refinements in cellular, genetic and molecular methods in recent years have opened up unexplored avenues in geme research. The modern tools of gene and geme analyses, coupled with analysis of finer segments of gene sequences in chromosomes utilizing molecular hybridization, are w applied on a wider scale in different groups of plants, ranging from algae to angiosperms. The present series on Plant Gemics: Biodiversity and Evolution aims to cover, in successive volumes, comprehensive reviews, concepts and discussions on the results of geme analysis and their impact on systematics, taxomy, phylogeny and evolution of all plant groups. This volume touches upon the Lower Groups of plants.