In 1879, some twenty years after the publication of his famous Origin of Species, Charles Darwin wrote a letter to botanist Dr Joseph Hooker. One sentence in particular underscored a vexing problem for evolutionary theory: “The rapid development as far as we can judge of all the higher plants within recent geological times is an abominable mystery.” By ‘higher plants’ Darwin had in mind the plants he viewed as being the most ‘highly evolved’, i.e. the Angiosperms—plants with flowers (with seeds produced inside the female reproductive organ). As BBC Science put it, “The famous naturalist was haunted by the question of how the first flowering plants evolved.”