<i>Cystoderma yongpingense</i> sp. nov. (<i>Squamanitaceae, Agaricales</i>) a new species from southwestern China

Abstract

The genus Cystoderma Fayod was established by Fayod in 1889 (Fayod, 1889), and later C. amianthinum (Scop.) Fayod was designated as the type species by Smith andSinger in 1945 (Smith &Singer, 1945). This genus is characterized by distinctive features in its basidiocarps, such as the globose cellular structure in the veil tissues, the weakly to strongly amyloid basidiospores, and a variable annulus on the stipe which can be either evanescent and floccose-scaly or persistent and membranous (Saar, 2012). These basidiocarps are commonly found in habitats like moss, forest litter, or decaying wood beneath coniferous or broadleaved trees (Saar et al., 2016).The genus Cystoderma, originally classified under the Lepiota section of the Agaricus by Persoon in 1797 (Persoon, 1797), has undergone significant taxonomic revisions over the years. In 1945, Smith and Singer published the first monograph on the genus, categorizing the taxa into two distinct sections: Granulosa and Amianthina (Smith & Singer, 1945). However, in 1962, Singer renamed the Amianthina section to Cystoderma (Singer, 1962). Later, in 2002, after assessing the taxonomic significance of spore amyloidity in the genus Cystoderma, Harmaja (2002) took into account the findings from research on the nuclear DNA content of specific species (Saar & Kullman, 2000) and the phylogenetic analysis of nucLSU data (Moncalvo et al., 2002), further classifying Cystoderma into two genera: Cystoderma, which is placed in the family Squamanitaceae, and Cystodermella, whose phylogenetic position remains unknown for the time being (Liu et al., 2021).During the course of researching macrofungi in southwestern China, we discovered a Cystoderma species with distinct light orange-red to orange-red coloration. The specimen was collected from a broadleaf forest in Yongping County, Yunnan Province. We have identified it as a new species based on morphological characteristics and molecular analyses.The specimens have been deposited at the Kunming Edible Fungi Institute of All China Federation of Supply and Marketing Cooperatives, Kunming, China (KEF). These specimens were collected in the field following photographic documentation. Microscopic exminations and measurements were carried out using a Leica DM5000B microscope, following procedures described by Li et al. (2022). The dimensions of microscopic features, including spores and basidia, were determined in Melzer's reagent solution based on more than 20 measurements for each feature. Molecular and phylogenetic analysesDNA was extracted from dried specimens using a BEIWO Fungal gDNA Isolation Kit (Biomiga, China) according to the manufacturer's instructions with some modifications. The ITS region was amplified using ITS4 and ITS5 primers (White et al., 1990), while the nrLSU region was amplified using LROR (Cubeta et al., 1991) and LR5 primers (Vilgalys &Hester, 1990). PCR products were