One of the quintessential Mesozoic plants, Cycadeoidea was not a true cycad, but a member of the extinct Bennettitales. Unlike the profusely branched forms of the Williamsoniaceae (such as Kimuriella), Cycadeoidea had short, stout trunks that looked superficially like modern cycads. These trunks were covered in large, diamond-shaped leaf bases, forming a scale-like armor.

The pseudo-flowers of Cycadeoidea were embedded within the trunk itself, nestled between the leaf bases. These bisporangiate cones (containing both male and female structures) are thought to have remained closed at maturity. Because of this, some researchers have proposed they were self-pollinated. However, many fossil cones also preserve intricate networks of tunnels made by wood-boring beetles, suggesting a unique form of insect pollination.

Cycadeoidea is found in fossil beds across North America, Asia and Europe, and likely occupied semi-arid, open habitats. With their compact growth form and armored stems, these plants were well-suited to drought and disturbance, and may have been common components of Late Jurassic and Early Cretaceous lowland vegetation.