New Genus Lasiolepiota Adds Two Species to Southeast Asian Agarics

A team of mycologists led by Phongeun Sysouphanthong and colleagues announced the first description of the fungal genus Lasiolepiota on October 30 2026 in the open-access journal MycoKeys¹. The publication reports that specimens were collected from forests of Laos and Thailand, where they identified two novel species named Lasiolepiota oinochroa and Lasiolepiota thailandica. Each species was described using detailed morphological observations coupled with molecular data, establishing the genus as part of the family Agaricaceae s.str.¹

The defining macroscopic characters include a glabrous patch at the center of the pileus, while the basidiomata are covered by a thick layer of fibrous felt or woolly floccules. Lamellae are free, white, and lack pleurocystidia; an annulus is present but fragile. Microscopy revealed a complex hyphal structure composed of irregular and branched hyphae, with hyaline ellipsoid to amygdaliform basidiospores, clavate to fusiform cheilocystidia. These features differentiate Lasiolepiota from other genera within Agaricaceae¹

To confirm phylogenetic placement, the authors performed multigene analysis combining ITS, LSU, rpb2, and tef1-α sequence data. The resulting tree placed Lasiolepiota firmly within Agaricaceae s.str., showing clear separation from all previously known genera in the family. This genetic evidence supports the distinctiveness suggested by morphology and provides a robust framework for future taxonomic work in this group¹

The discovery expands our understanding of Agaricales diversity particularly across Southeast Asia where many fungal lineages remain underexplored. By adding two new species and establishing a separate genus, the study highlights morphological characters—such as the unique pileus patch and fibrous surface—that can be used by field mycologists and mushroom foragers to distinguish these taxa in situ¹

Expert notes accompanying the publication emphasize that this description offers valuable insights into the unique morphological traits that set Lasiolepiota apart from existing agarics.

In sum, the introduction of Lasiolepiota not only adds two new species to the fungal catalog but also underscores the importance of integrating detailed morphology with multigene phylogenetics in uncovering hidden diversity in well-studied families like Agaricaceae. The work sets a precedent for further exploration of Southeast Asian basidiomycetes and may inform both scientific research and practical applications such as biodiversity monitoring and sustainable harvesting practices.