How did Darwin’s ideas about evolution influence plant classification?

Charles Darwin’s theory of evolution fundamentally transformed plant classification by shifting the goal of taxonomy from grouping organisms based on superficial similarities to reflecting their natural relationships through evolutionary descent.12

Before Darwin, biological classifications were often "artificial," relying on arbitrary traits or "natural characters" that lacked a theoretical basis for why organisms formed specific hierarchies. Darwin’s On the Origin of Species (1859) provided the necessary framework to explain these relationships: degrees of resemblance between plant groups correspond to their degree of relationship from common ancestors.231

The influence of Darwinian thought on botany includes:

• Phylogenetic Systems: Modern classification is phylogenetic, meaning plants are arranged based on their evolutionary history rather than just external morphology.2
• Interpretation of Affinity: Taxonomists began to recognize that what was previously described as "natural affinity" was actually the result of evolutionary lineage.4
• Shift in Methodology: While the immediate impact on some groups was negligible or led to speculative reclassifications, the long-term impact established the tree of life as the conceptual goal for systematic botany.14

Today, this approach is coordinated through international efforts like the Angiosperm Phylogeny Group, which uses molecular and phylogenetic data to refine our understanding of plant lineages.52