The evolutionary history of flowering plants

Abstract

In terms of species richness and important ecological roles, there are few biological groups that rival the success of flowering plants (Angiospermae). Angiosperm evolution has long been a topic of interest, with many attempts to clarify their phylogenetic relationships and timescale of evolution. However, despite this attention there remain many unsolved questions surrounding how and when flowers first appeared, and much of the angiosperm diversity remains to be quantified. Here, I review the evolutionary history of angiosperms, and how our understanding of this has changed over time. I begin by summarising the incredible morphological and genetic diversity of flowering plants, and the ways in which this can be studied using phylogenetic inference. I continue by discussing both the relationships between angiosperms and the other major lineages of seed plants, and the relationships between the main groups within angiosperms. In both cases, I outline how our knowledge has changed over time based on factors such as the different conclusions drawn from morphological and genetic data. I then discuss attempts to estimate the timescale of angiosperm evolution and the difficulties of doing so, including the apparent conflict between ages derived from fossil and molecular evidence. Finally, I propose future directions for angiosperm research to help clarify the evolutionary history of one of the most important groups of organisms on the planet.