Weichselia is a unique and iconic Mesozoic fern, unlike anything alive today. It was historically placed in the fan-fern family (Matoniaceae) due to its similarly shaped fronds, though its true relationships remain uncertain. Recent studies suggest it may instead belong to the giant fern family (Marattiaceae), though this remains unresolved.

Weichselia is remarkable for both its striking appearance and unusual habitat among ferns. It was a massive plant, with circular fronds over 2 meters across and fossilized stem segments reaching up to 8 meters in length. These stems also show evidence of aerial roots, which may have functioned like those of modern mangroves, providing support and aiding nutrient uptake in brackish or salt-influenced environments.

Ubiquitous during the Early to mid-Cretaceous, Weichselia dominated coastal and lagoonal habitats across the globe. Its fossils have been found at iconic sites like the Bernissart Iguanodon Pit and the mangrove-like wetlands of the Bahariya Formation, home of Spinosaurus. Like many hallmark Mesozoic plants, its range sharply declined in the Late Cretaceous, likely in response to the rise of flowering plants, and it ultimately went extinct before the end of the period.