DNA Barcodes Reveal Hidden Jelly Fungus Diversity Across China

A gelatinous mushroom with tiny teeth instead of gills, long treated as one cosmopolitan species, is turning out to be a crowd of lookalikes. In a new taxonomic revision published in MycoKeys, researchers combined DNA sequences from three genetic markers with detailed morphological study to untangle the toothed jelly genus Pseudohydnum in China. The team formally described three new species, refined the boundaries of four previously known taxa, and recorded the genus growing on bamboo for the first time anywhere in the world. The work also confirmed what earlier molecular surveys had hinted at: morphology alone is currently insufficient to delimit species in this group, because convergent or plastic characters obscure the diagnostic differences that DNA reveals.

Pseudohydnum belongs to the order Auriculariales within the Basidiomycota and is characterized by gelatinous, stalked to sessile fruiting bodies, a hydnoid hymenophore studded with tooth-like spines, globose to ellipsoid basidiospores, and longitudinally septate basidia. Although initially placed in Tremellales on the basis of basidial morphology, the genus was reclassified into Auriculariales in 1984, a placement later confirmed by molecular phylogenetics, though its familial position within the order remains unresolved. In China, members are known colloquially as cat’s tongue or tiger’s paw mushrooms and are valued both as edible fungi and as sources of bioactive compounds.

For decades the genus was dominated by its type species, Pseudohydnum gelatinosum, regarded as a morphologically uniform and cosmopolitan taxon reported from Europe, Asia, the Americas, and Oceania. Early mycologists had already noted morphological variation among collections, especially from tropical regions, hinting at overlooked diversity. Molecular tools fundamentally reshaped that picture, revealing that P. gelatinosum in the broad sense represents a complex of phylogenetically distinct lineages rather than a single widespread species. Recent revisions integrating multi-marker DNA data with detailed morphology expanded known diversity further: one study re-established an older name and described six new species from Eurasia and North America, while another unveiled four new Neotropical species from Brazil, underscoring that diversity in tropical and subtropical ecosystems is substantially underestimated and geographically structured.

China has become the center of that discovery wave. After the first modern Chinese species, P. brunneiceps, was described in 2020, subsequent studies added five more species, and intensive surveys on the Qinghai-Xizang Plateau revealed four additional new species alongside the first national records of two Eurasian taxa. The most recent additions brought P. fusiforme, P. incarnatum, and P. rhododendri from Guangxi and Xizang, together with the first Chinese record of P. umbrosum. To date the genus comprises 28 widely accepted taxa, 27 species and one subspecies, with China harboring the majority of known global diversity. Yet the inventory remains incomplete: many historical records rest solely on morphology and likely encompass cryptic species, phylogenetic relationships among Chinese taxa and their links to lineages elsewhere are not fully resolved, and intraspecific variation is poorly documented.

The new study drew on fresh basidiomata collected and photographed in the field from Anhui, Xizang, and Yunnan provinces between 2016 and 2025. Vouchers were deposited in the Mycological Herbarium of Kunming Medical University and the Herbarium Mycologicum Academiae Sinicae. Thirty-five specimens were selected for molecular analysis, and genomic DNA was extracted for PCR amplification of the nuclear ribosomal internal transcribed spacer region, the nuclear large subunit ribosomal DNA gene, and the RNA polymerase II largest subunit gene. The resulting phylogeny was built from 211 sequences, 92 newly generated and 119 retrieved from GenBank, representing 92 collections, with two species of the genus Stypellopsis serving as outgroups. Sequences were aligned with MAFFT, concatenated, and analyzed under both maximum likelihood and Bayesian inference; the concatenated ITS-nrLSU-rpb1 dataset comprised 2,449 aligned nucleotide sites including gaps, split as 669 from ITS, 893 from nrLSU, and 887 from rpb1. The two inference methods produced highly congruent, well-resolved topologies with only minor differences at weakly supported nodes.

The multi-marker phylogeny unambiguously resolved the 35 newly collected Chinese specimens into nine strongly supported terminal clades. Four clades matched known Chinese species: P. brunneiceps, P. fusiforme, P. laricicola, and P. sinogelatinosum, assignments based on both sequence identity and morphological concordance with their protologues. The remaining five clades could not be confidently matched with any described species; three are formally proposed as new species, while two, informally labeled Pseudohydnum sp. 1 and sp. 2, await more complete sampling. Each new taxon occupies a strongly supported, phylogenetically distinct position. Pseudohydnum ellipsosporum, with bootstrap support of 100 percent and a Bayesian posterior probability of 1.00, was recovered as sister to the northeastern Chinese P. sinobisporum. Pseudohydnum macroumbrosum, supported by a bootstrap value of 100 percent and a posterior probability of 0.96, formed a well-supported sister clade to the Far Eastern P. umbrosum. Pseudohydnum roseolostipitatum, with bootstrap support of 82 percent, emerged as a distinct lineage sister to a Qinghai-Xizang Plateau clade containing P. himalayanum and an undescribed phylogenetic species.

Pseudohydnum ellipsosporum, known only from Yunnan, produces large, gelatinous, laterally stipitate fruiting bodies with a pileus up to 55 millimeters wide, a dark olive-brown surface, and ellipsoid to elongate basidiospores measuring 9.0 to 11.7 by 5.5 to 7.0 micrometers. It grows on decayed wood of Picea and Taxus and differs from its sister species P. sinobisporum, which has a smaller ivory pileus up to 12 millimeters, shorter and more rounded spores, and predominantly two-spored basidia. Pseudohydnum macroumbrosum, also known only from Yunnan, is the giant of the group: its pileus reaches 110 millimeters in widest diameter and 10 millimeters thick, its stipe runs 30 to 60 millimeters long, and its subglobose to broadly ellipsoid spores measure 8.3 to 10.0 by 7.3 to 8.7 micrometers. It grows gregariously or imbricately on decayed Pinus armandii wood and is sister to P. umbrosum, which has nearly sessile basidiomata, a pileus no larger than 20 millimeters, and narrower spores. Pseudohydnum roseolostipitatum, likewise known only from Yunnan, bears a pinkish gray to cinnamon brown pileus up to 45 millimeters wide, a well-developed clavate stipe that expands at a sometimes bulbous base, and globose to subglobose spores of 7.0 to 8.3 by 6.5 to 7.8 micrometers, growing on decayed Abies wood.

Among the previously known taxa, the most striking ecological finding concerns P. brunneiceps. Originally described from Jiangxi on decayed coniferous wood, particularly Cryptomeria japonica, and later documented from Hunan on similar substrates, the species was previously reported as exclusively conifer-associated. All Anhui specimens in the new study, however, were consistently found on decayed bamboo, Phyllostachys edulis, indicating a broader host range than previously recognized and, to the authors’ knowledge, the first record of any Pseudohydnum species on bamboo. The Anhui collections also extend the species’ known distribution, where it is locally common and harvested for consumption in southern montane areas.

The revision also documented considerable intraspecific variation that had been historically underestimated. In P. sinogelatinosum, one of the most common representatives of the genus in subalpine Himalayan regions, pileus color ranges continuously from white through grayish white, pale brown, brown, dark brown, cinnamon, to clay-pink, and the surface varies from smooth to densely covered with minute spines, essentially encompassing the macromorphological range of nearly half the known species. Comparable variation appeared in P. fusiforme, newly reported from Yunnan, whose specimens showed subsessile to laterally stipitate basidiomata, denser spines of three to five per millimeter, slightly wider and more globose spores, and a previously undocumented ontogenetic color change progressing from white to watery-grayish, clay-pink, and ultimately brown. In P. laricicola, first recorded in Yunnan, the basidiomata were notably larger than in the original description, with a pileus up to 50 millimeters versus 20 to 30 millimeters, and the spores slightly wider, discrepancies the authors attribute to the original description having been based on immature or incompletely developed specimens.

The biogeographic patterns emerging from the phylogeny are equally telling. Pseudohydnum ellipsosporum is sister to the temperate northeastern Chinese P. sinobisporum, yet the two differ markedly in spore shape and basidial spore number, implying that latitudinal climatic differentiation may have driven allopatric divergence. Pseudohydnum macroumbrosum forms a sister lineage to the Far Eastern P. umbrosum but possesses strikingly larger basidiomata and more globose spores, suggesting geographic isolation promoted morphological divergence. Pseudohydnum roseolostipitatum, closely related to the Qinghai-Xizang Plateau-endemic P. himalayanum, is clearly separated by stipe development and pileus color, a divergence the authors plausibly explain by niche differentiation while noting the hypothesis requires further ecological testing. Recurring stipe reduction across multiple independent lineages offers a valuable opportunity for future ancestral-state reconstruction and phenotype-environment association analyses. The findings substantially expand the known taxonomic and ecological diversity of Pseudohydnum in Asia and suggest that China, particularly the Qinghai-Xizang Plateau, may be a global hotspot for the genus, while two informally designated lineages hint that hidden diversity may be considerably higher than currently recognized.

Subject of Research: Integrative taxonomy of the toothed jelly fungus genus Pseudohydnum in China using multi-marker phylogeny and morphology

Article Title: Integrating multi-marker phylogeny and morphology reveals hidden diversity and intraspecific morphological variation in the genus Pseudohydnum P. Karst. ( Basidiomycota , Auriculariales ) from China

Article References: Yu, T.-J., Zhang, W.-H., Li, X.-J., Xiong, Y.-Y., Gao, Y.-X., Li, T., Xue, R., Lu, Y.-T., Xu, C., Li, J., & Tang, L.-P. (2026). Integrating multi-marker phylogeny and morphology reveals hidden diversity and intraspecific morphological variation in the genus Pseudohydnum P. Karst. (Basidiomycota, Auriculariales) from China. MycoKeys, 142, 265–291. https://doi.org/10.3897/mycokeys.142.215470

Image Credits: AI Generated

DOI: 10.3897/mycokeys.142.215470

Keywords: Pseudohydnum, jelly fungi, Auriculariales, integrative taxonomy, phylogenetics, China, Qinghai-Xizang Plateau, new species, bamboo host, cryptic diversity, morphological variation, ITS-nrLSU-rpb1