Lichen Taxonomy and Systematics 

Mohammad Sohrabi

Introduction: Lichen Taxonomy and Systematics

Lichen taxonomy and systematics form the foundational framework for understanding the diversity, evolution, and ecological roles of lichenized fungi. Taxonomy—the science of naming, describing, and classifying organisms—has long played a central role in lichenology, historically grounded in morphological and anatomical characteristics of the fungal partner (mycobiont), the photobiont, and the structure of the symbiotic thallus. Systematics, which encompasses taxonomy, further incorporates phylogenetic relationships to reconstruct evolutionary histories, thereby offering a more holistic view of lichen diversity.

Over the past few decades, the field has undergone a transformative shift through the integration of molecular phylogenetics, chemical profiling (via secondary metabolites), and ecological data. These advances have led to the discovery of numerous cryptic species, redefinition of traditional genera and families, and the reorganization of long-standing classification schemes. Lichen systematics today is a dynamic field, bridging classical taxonomy with cutting-edge genomic tools, and is essential for biodiversity assessment, conservation biology, environmental monitoring, and the broader understanding of fungal evolution.

MYCOLICH website provides a comprehensive overview of the principles, methodologies, and practical approaches used in modern lichen taxonomy and systematics. Designed for both early-career researchers and experienced lichenologists, it aims to equip readers with the tools and knowledge needed to study, identify, classify, and interpret the evolutionary relationships of lichens in a contemporary context.

Chapters

1. Chapter 1: History and Principles of Lichen Taxonomy
   
   

2. Chapter 2: Morphological and Anatomical Characters in Lichen Identification
   
   

3. Chapter 3: The Role of Secondary Metabolites in Taxonomy (Chemotaxonomy)
   
   

4. Chapter 4: Photobiont Diversity and Its Taxonomic Significance
   
   

5. Chapter 5: Molecular Tools in Lichen Systematics (DNA Barcoding and Sequencing)
   
   

6. Chapter 6: Phylogenetic Analysis and Tree Reconstruction
   
   

7. Chapter 7: Species Concepts in Lichenology: Morphological, Biological, and Phylogenetic Approaches
   
   

8. Chapter 8: Taxonomic Databases, Digital Resources, and Nomenclatural Codes
   
   

9. Chapter 9: Typification, Holotypes, and the Use of Historical Collections
   
   

10. Chapter 10: Case Studies in Lichen Taxonomy: Revising Complex Groups
    
    

11. Chapter 11: Integrative Taxonomy and the Future of Lichen Systematics
    
    

12. Chapter 12: Field and Laboratory Techniques in Lichen Taxonomic Research
    
    

13. Chapter 13: Geographic Information Systems (GIS) and Biogeographical Patterns in Lichens
    
    

14. Chapter 14: The Role of Taxonomy in Lichen Conservation and Biodiversity Policy