Flowers appear

The first unambiguous angiosperm pollen and fossils appear in the Early Cretaceous, from a lineage whose deeper origin is still argued over — molecular clocks have placed the crown group anywhere from 250 to 140 million years ago, well before anything shows up in the rocks, a mismatch Darwin called an abominable mystery. What is not in doubt is what follows. The flower is a device for making animals do the work of pollination, and the fruit is a device for making them do the work of dispersal. Both convert plants from passive to transactional, and the deal reshapes almost every terrestrial ecosystem on Earth.