Introduction

Plants are perhaps the most fundamental form of life, providing sustenance, and thus enabling the existence of all animals, including us humans. Their evolutionary transition from Paleozoic aquatic beginnings to a vegetative life out of water is undoubtedly one of the farthest reaching events in the history of the earth. It was the silent yet relentless colonization of terrestrial environments by the earliest land plants that transformed the global landscape and radically altered the geochemical cycles of the planet. This resulted in lowered concentrations of atmospheric carbon dioxide and thus set the scene for the emergence of terrestrial animals about 350 million years ago. Over the subsequent circa 200 million years, as Mesozoic forests of ferns, conifers, and cycads flourished and the first flowering plants made their appearance, so the first reptiles, and then mammals and birds emerged.