These flowers have large feathery stamen and produce a high volume of pollen, as they rely on wind pollination.

This region at the time would have had a Mediterranean climate due to the proximity of the Tethys Sea, which covered parts of present-day Tibet and Xinjiang into the early Tertiary period.

The other genera include a number of popular ornamental trees, widely planted in parks and large gardens; several of the birches are particularly valued for their smooth, brightly coloured bark.

The wood is generally hard, tough and heavy, hornbeams particularly so; several species were of significant importance in the past where very hard wood capable of withstanding heavy wear was required, such as for cartwheels, water wheels, cog wheels, tool handles, chopping boards, and wooden pegs.

Modern molecular phylogenetics suggest the following relationships:[3][4][5] Myricaceae (outgroup) Corylus Ostryopsis Ostrya Carpinus Alnus Betula