Arbre évolutif des plantes à fleurs, avec au centre la fleur ancestrale

Tree diagram showing the evolution of flowering plants, with at its centre the common ancestor of all flowers, which appeared approximately 140 million years ago. Flowering plants (angiosperms) form the world's most diversified plant group, with more than 300,000 species. They are thought to have developed and diversified particularly rapidly during the Cretaceous Period. This observation was a source of interest among the scientific community. By combining data on flower structures with the most recent flowering plant evolutionary tree, informed by genetic information relating to the constituent species, scientists have posited a scenario to account for this diversification in flower shapes and model the ancestral flower. This ancestral flower is thought to have been hermaphroditic, containing both female parts (carpels) and male parts (stamens). The flower consisted of verticils - petal-like organs - organised in groups of three. This observation contradicts the prevailing assumption that the ancestral flower had all its organs arranged in a spiral. This discovery does not, however, resolve all the mysteries surrounding the origins of flowering plants. The fossil register of these plants is still far from complete, for example.