Michael Simpson is a Professor Emeritus of Botany who is the Author of one of the best textbooks available on the evolutionary history, grouping and Identification of plant species - Plant Systematics. 
 
Taxonomy, Evolution, & Diversity of Plants on Earth? What are phylogenetics? What is a "biogeography dungeon" and why is it fascinating as shit to be trapped inside? What causes one to go down a wormhole of obsession with the various forms that plants can take?