With one new volume each year, this series keeps scientists and advanced students informed of the latest developments and results in all areas of botany. The present volume in- cludes reviews on structural botany, taxonomy, geobotany, plant physiology, genetics, and floral ecology.

Review.- Archaea (Archaebacteria).- A. Structural Botany.- I. Cytology and Morphogenesis of the Prokaryotic Cell.- II. Cell Architecture and Cellular Morphogenesis of Eukaryotic Algae (Rhodophyta and Phaeophyta).- III. Phloem Regeneration.- IV. Reproductive Development in Seed Plants: Research Activities at the Intersection of Molecular Genetics and Systematic Botany.- B. Physiology.- I. Plant Water Relations.- II. The Transport Phloem. Specifics of its Functioning.- III. Progress in Chlorophyll Fluorescence Research: Major Developments During the Past Years in Retrospect.- IV. Photosynthesis: Carbon Metabolism Twenty Years of Following Carbon Cycles in Photosynthetic Cells.- V. Metabolism of Inorganic Nitrogen Compounds.- VI. Secondary Plant Substances Further Topics of the Phenylpropanoid Metabolism.- VII. Mineral Nutrition: Tropical Savannas.- VIII. Developmental Physiology: Signal Transduction.- C. Genetics.- I. Replication.- II. Recombination: Sexual Reproduction — a Tool for Outcrossing and Recombination of Genetic Material.- III. Isolation of Plant Genes by T-DNA and Transposon Mutagenesis — Gene Tagging.- IV. Function of the Genetic Material: Transposable Elements in Lower Eukaryotes.- V. Extranuclear Inheritance: Mitochondrial Genetics.- VI. Extranuclear Inheritance: Linear Protein-Primed Replicating Genomes in Plants and Microorganisms.- VII. Molecular Genetics of Phytopathogenic Fungi.- D. Taxonomy.- I. Systematics of the Bryophytes.- II. Systematics of the Pteridophytes.- E. Geobotany.- I. The History of Flora and Vegetation During the Quaternary.- II. Plant Geography.- III. Ecological Aspects of Nitrogen Nutrition.- F. Special Topics.- I. Floral Ecology Report on the Years 1988 (1987) to 1991 (1992).- II a. Mycorrhizae: Ectomycorrhiza andEctendomycorrhiza.- II b. Symbioses: Mycorrhizae.