A Chinese forest fungus nicknamed D-rex grows to 50 centimeters, roughly double the old record for its group

A fungus from the forests of Yunnan Province, China, has been described with fruiting bodies up to 50 centimeters tall and 2.2 kilograms in weight, roughly double the 20 to 30 centimeters recorded before for its group. Its describers named it Dianjunus rex and nicknamed it “D-rex,” and they placed it in a new genus and a new family, Dianjunaceae, within the order Xylariales. The claim of record size is the authors’ own, made in a formal species description rather than a field report.

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Ascomycetes are the sac fungi, a vast group that includes yeasts, morels, truffles and the wood-decay fungi called Xylariales. Most of their visible structures are small. Against that background an upright, stalked structure half a meter tall stands out, and it is the reason the description drew attention beyond mycology journals when the paper appeared in late September 2026.

Fifty centimeters and 2.2 kilograms

The study, published in Frontiers in Fungal Biology, reports fruiting bodies, called stromata, that are upright and fleshy. The fertile upper part measures 10 to 20 centimeters high and 7 to 10 centimeters across on a sterile stalk 20 to 30 centimeters tall, and individual specimens reach about 2.2 kilograms. The authors say these are the largest fruiting structures documented in Ascomycota, and they report that tropical specimens grew larger than subtropical ones.

The news release distributed through EurekAlert frames the comparison in height: the previous record-holders among ascomycete fruiting bodies stood 20 to 30 centimeters tall, so 50 centimeters is roughly double. One caution applies to the word record. In the paper, the comparison species is Engleromyces goetzei from Kenya, which has a diameter near 30 centimeters and a weight of about 3.2 kilograms, so the doubling describes height and overall size rather than every measure of mass.

Cork oak roots at three Yunnan sites

The specimens came from three localities: Damaidi Village in Luquan County, Kunming; Nanbang Village in Mengla County, Xishuangbanna; and Yipinglang Town in Lufeng City, Chuxiong. The release describes temperate coniferous forest near Damaidi and Yipinglang and tropical rainforest near Nanbang. The fungus emerges from the soil around the roots of dying host plants, and the holotype, the single specimen that anchors the species name, was associated with Quercus variabilis, the Chinese cork oak.

A team led by Dr. Indunil C. Senanayake of the Germplasm Bank of Wild Species at the Kunming Institute of Botany, Chinese Academy of Sciences, with colleagues from China, Thailand and Mexico, collected the material and deposited voucher specimens at the institute. Popular Science reported that the fungus typically grows on woody roots of the cork oak, and that the team also found fruiting bodies emerging from fallen wood.

A family traced to the aftermath of the dinosaurs

Genetic work supports the naming. The team ran a multilocus analysis and sequenced the genome, and the results placed Dianjunaceae as a sister lineage to Graphostromataceae, whose closest known member, Graphostroma platystoma, grows on dead hardwood across the Northern Hemisphere. A molecular clock calibrated against hundreds of fungi of known age dates the new family to about 65 million years ago, roughly a million years after the mass extinction that ended the age of the dinosaurs, with an uncertainty range of 50 to 80 million years in the paper.

Senanayake said the species “provides a rare window into the evolution of extreme fungal body forms,” and said it illustrates how much fungal diversity remains undiscovered in East Asian forests, as Gizmodo’s account of the study relays. On the timing near the extinction, Senanayake said the timing “raises an intriguing possibility,” and that choice of words is a hedge rather than a finding, in keeping with how the authors frame the post-extinction link throughout. The authors propose that forests after the extinction held large amounts of dead plant material, which may have opened opportunities for wood-decomposing fungi; they describe that as a possibility, not a demonstrated cause.

Why height may matter for spores

On the question of why a fungus would grow so tall, the authors suggest that height may improve wind dispersal of spores in dense forest. They note that building such a structure is energetically costly, so it likely evolved only where the benefits outweighed the costs. The genome also contains genes for enzymes that break down tough plant material, a trait common in Xylariales that may help the fungus digest dead wood. Gizmodo’s summary adds that the fungus appears to need little metabolic maintenance, a detail reported by that outlet from the study. Readers weighing the record claim should keep the species description itself in view, since the height comparison, the host plant and the dating all rest on the authors’ measurements and analyses.

The formal name reflects the fungus’s regal size and the ancient Dian kingdom of Yunnan, while “D-rex” is a nickname that echoes the dinosaur. The full paper, available under its digital object identifier, remains the place to check the measurements, specimen details and the authors’ reasoning on how the family arose.

This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.

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