These ancient, flower-like plants dominated the Mesozoic before vanishing alongside the dinosaurs.

Gardening · Published 3 October 2026 Swipe more like this →

In short: Bennettitales were once among the most common seed plants on Earth, often mistaken for modern cycads. Yet, these mysterious gymnosperms possessed complex, flower-like reproductive organs and likely co-evolved with ancient insects. Their sudden decline during the Cretaceous remains a fascinating puzzle in the history of botanical evolution.

First appearing in the early Permian about 281 million years ago, Bennettitales were a cornerstone of Mesozoic flora. While their foliage is nearly indistinguishable from cycads, they are anatomically distinct. The most reliable way to tell them apart is by examining their stomata; bennettitalean guard cells and subsidiary cells share a common origin, a syndetocheilic structure that differs fundamentally from the haplocheilic arrangement found in cycads.

The order is divided into two primary families with distinct growth habits. The Cycadeoidaceae featured stout, cycad-like trunks and bisporangiate cones, while the Williamsoniaceae grew as slender, branching woody shrubs. Some of these reproductive structures were so complex that early researchers labeled them flowers, though they are not true angiosperms. Evidence suggests some species, such as those with the reproductive structure Williamsoniella, may have relied on insects with long proboscises for pollination, as indicated by fossilized flies from the Zhangsolvidae family.

The evolutionary position of Bennettitales is heavily contested. Early 20th-century theories suggested they were the ancestors of flowering plants, a hypothesis later challenged by molecular evidence. Modern studies have explored links to gnetophytes and other gymnosperms, but their exact placement remains uncertain. By the end of the Cretaceous, as flowering plants rose to prominence, Bennettitales suffered a severe decline. Their final known remains date to the Maastrichtian, though inconclusive records suggest they might have persisted into the early Oligocene in Australia and Tasmania.

Taxonomically, the group has a complex history. William Buckland first identified the Cycadeoideaceae in 1828 from fossils on the Isle of Portland, while Adolf Engler formally erected the order in 1892. Today, they are typically classified within the class Bennettitopsida, serving as a reminder of a time when the world's forests were populated by plants that looked like modern cycads but functioned with the intricate, insect-attracting complexity of a flowering plant.

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