Deep within the forests of southwestern China, researchers have discovered an unusual fungus that challenges previous assumptions about how large certain fungal structures can grow.
Named Dianjunus rex, the newly identified species produces towering reproductive structures reaching 50 centimetres in height and weighing up to 2.2 kilograms.
The discovery, published in Frontiers in Fungal Biology in October 2026, has revealed an entirely new fungal family with evolutionary roots stretching back approximately 65 million years.
An Extraordinary Discovery In China
Scientists from the Kunming Institute of Botany encountered the unusual fungus while exploring forests in Yunnan province. Specimens were collected from temperate coniferous forests near Damaidi and Yipinglang, as well as tropical rainforest near Nanbang. The fungus develops large, pale reproductive structures called stromata, which emerge from the ground around the roots of Chinese cork oak trees.
Unlike familiar mushrooms, these fungi belong to the Ascomycota group, whose members produce spores inside microscopic sac-like structures.
With reproductive structures reaching half a metre in height, the new species surpasses previously documented examples in this group, which typically reached a maximum of 20–30 centimetres.
Scientists Identify A New Fungal Family
To investigate the discovery, researchers examined the fungus's physical characteristics and analysed its genetic material.
They also cultivated spores under laboratory conditions to study its development. The results revealed something unexpected: the organism represented an entirely new species, genus and family. Scientists classified it within the order Xylariales and established the family Dianjunaceae.
The name Dianjunus rex reflects its remarkable dimensions and pays tribute to the ancient Dian kingdom associated with the region.
Its closest known relative is Graphostroma platystoma, a wood-associated fungus found across parts of the Northern Hemisphere.
A Survivor From An Ancient Lineage
Genetic analysis provided another remarkable insight into the organism's history. Using molecular clock techniques, researchers estimated that its evolutionary family originated approximately 65 million years ago. This places its emergence shortly after the mass extinction event that eliminated non-avian dinosaurs around 66 million years ago.
Scientists suggest that dramatic environmental changes following the extinction may have created opportunities for fungi capable of decomposing dead plant material. However, this remains a hypothesis rather than a confirmed explanation of the group's origins.
Why Does This Fungus Grow So Large?
The unusual size of Dianjunus rex raises important questions about its ecological adaptations. Researchers suggest that taller reproductive structures may help release spores above surrounding vegetation, allowing wind to carry them farther. However, developing such large structures requires considerable energy and resources.
Its size may therefore reflect an evolutionary advantage in particular forest environments.
Members of the Xylariales order also produce enzymes capable of breaking down complex plant materials, although the new species' precise ecological role requires further investigation.
What The Discovery Means For Science
The findings demonstrate how much fungal biodiversity remains undocumented, even in forests that have been studied for decades. Yunnan's varied habitats, relatively stable climate and complex ecological relationships provide favourable conditions for fungal diversity. Nevertheless, seasonal growth patterns and difficult field conditions make many species challenging to detect.
Further exploration could reveal additional organisms with unusual characteristics and ancient evolutionary histories.
The discovery expands scientific understanding of fungal evolution and highlights the importance of protecting forest ecosystems that may contain species still unknown to science.
