Giant Fungus Dianjunus rex Found in China Gets Its Own Family

A research team has described a giant fungus from the forests of Yunnan, China, that grows up to 50 centimeters tall. One specimen weighed as much as 2.2 kilograms. The organism, named Dianjunus rex, looks like thick fingers pushing up from the ground, with branching tips and none of the familiar mushroom cap.

The team, led by researchers at the Kunming Institute of Botany of the Chinese Academy of Sciences, collected the fungi between 2024 and 2025, mostly near the base of dead trees. Typical specimens weighed 250 to 600 grams. The heaviest was formed by two masses joined together. The large structure is the part that produces spores, which the fungus uses to reproduce, and spore-bearing bodies of this size are rarely seen in the fungal kingdom.

A new species, genus and family

Size was not the most surprising finding. After examining the fungus's physical structure and genes, the researchers concluded that it differed too much from its closest relatives to be placed in any existing family. They therefore created not only a new species but also a new genus and a new family.

To put that in perspective, lions, tigers and house cats belong to the cat family, while wolves and dogs belong to the dog family. Finding one new organism and having to add a whole new branch to the tree of life is unusual.

Why the name rex

The species name "rex" is the same word used in Tyrannosaurus rex, chosen by the team because of the fungus's imposing size.

Genetic analysis suggests the lineage split from its relatives about 65 million years ago. Dinosaurs such as T. rex went extinct roughly 66 million years ago, so the two events fall in nearly the same period. While the dinosaurs were disappearing, the line leading to this "D-rex" may have been branching off within the fungal world.

The discovery shows how much of the fungal kingdom remains undocumented, even for organisms large enough to be seen easily on a forest floor.