Cobbania is an extinct member of the duckweed family (Araceae), closely related to modern water cabbage (Pistia). In fact, it was originally assigned to that genus as Pistia corrugata, before detailed fossil evidence led to its reclassification. While many fossils across the Late Cretaceous of North America and Asia are still labeled under the older name, only two species, Cobbania corrugata from the Dinosaur Park Formation and Cobbania hickeyi from the Hell Creek Formation, have been formally described. Like its modern relatives, Cobbania was a free-floating aquatic plant. It formed rosettes of broad, trumpet-shaped leaves that rested on the water’s surface, supported by submerged roots. These plants were connected by stolons, allowing them to grow into large, floating mats that likely covered lakes and slow-moving rivers. Fossils of up to six connected individuals have been found together on a single slab, suggesting they formed dense, interlinked colonies. Fossils of Cobbania are known from several Late Cretaceous formations across North America and Asia, indicating it was widespread across the Northern Hemisphere during the final chapters of the Mesozoic.