Reconstructed setting· The columns of time

Mesozoic world

252 Ma → 66 Ma

This backdrop shows the Mesozoic: a canopy of conifers, cycads and ferns above large vertebrates, with flowering plants appearing only in the Cretaceous.

Backdrop representing a canopy of conifers, cycads and ferns above large vertebrates, flowering plants appearing only from the Cretaceous, the last of the era's three periods.

What the evidence shows

The flora of the early Mesozoic was dominated by gymnosperms, seed plants without flowers, hence this cover of needles and fronds. Flowers are depicted only from 145 million years, the diversification of angiosperms having begun in the Early Cretaceous and continued through the Late Cretaceous: a composition showing flowers across the whole era would place at the wrong moment the most important transformation in the history of terrestrial vegetation. Large herbivores appear because vertebrate herbivory conditions the body sizes that characterise the era.

Bounds and conventions

Three documented propositions for 186 million years, which is few. The flora is established from northern hemisphere data; the southern continents are, for the same interval, less well documented and probably carried a different vegetation.