Cycads have a bare, central trunk that is topped by a crown of long leaves.
They are drought tollerant and well protected by armour-like bark and spiny leaves with thick cuticles. They first appear in deposits from the Late Triassic period and became common in the Jurassic. They declined in diversity in the Late Cretaceous period. They are similar in appearance to the tree ferns and palms but have a distinctive method of reproduction. Cycads are seed-bearing plants, or gymnosperms, and produce cones in the centre of the crown with male and female types on separate plants.