Plant Taxonomy: A Historical Perspective, Current Challenges, and Perspectives

Taxonomy is the science that explores, describes, names, and classifies all organisms. In this introductory chapter, we highlight the major historical steps in the elaboration of this science, which provides baseline data for all fields of biology and plays a vital role for society but is also an independent, complex, and sound hypothesis-driven scientific discipline. In a first part, we underline that plant taxonomyTaxonomy is one of the earliest scientific disciplines that emerged thousands of years ago, even before the important contributions of the Greeks and Romans (e.g., Theophrastus, Pliny the Elder, and Dioscorides). In the fifteenth–sixteenth centuries, plant taxonomyTaxonomy benefited from the Great Navigations, the invention of the printing press, the creation of botanic gardens, and the use of the drying technique to preserve plant specimens. In parallel with the growing body of morpho-anatomical data, subsequent major steps in the history of plant taxonomyTaxonomy include the emergence of the concept of natural classification Classifications , the adoption of the binomial naming system (with the major role of Linnaeus) and other universal rules for the naming of plants, the formulation of the principle of subordination of characters, and the advent of the evolutionary thought. More recently, the cladistic Cladistics theory (initiated by Hennig) and the rapid advances in DNA technologies allowed to infer phylogenies and to propose true natural, genealogy-based classificationsClassifications. In a second part, we put the emphasis on the challenges that plant taxonomyTaxonomy faces nowadays. The still very incomplete taxonomic knowledge of the worldwide flora (the so-called taxonomic impediment) is seriously hampering conservationConservation efforts that are especially crucial as biodiversity has entered its sixth extinction crisis. It appears mainly due to insufficient funding, lack of taxonomic expertise, and lack of communication and coordination. We then review recent initiatives to overcome these limitations and to anticipate how taxonomyTaxonomy should and could evolve. In particular, the use of molecular data has been era-splitting for taxonomyTaxonomy and may allow an accelerated pace of species discovery. We examine both strengths and limitations of such techniques in comparison to morphology-based investigations, we give broad recommendations on the use of molecular tools for plant taxonomyTaxonomy, and we highlight the need for an integrative taxonomyIntegrative taxonomy based on evidence from multiple sources.