New Contributions to Entoloma sect. Madida (Entolomataceae, Agaricales) from Subtropical Montane Forests of China: Two New Taxa

Entoloma is a species-rich and taxonomically complex genus in Entolomataceae, characterised by pink to pinkish-brown spore prints and angular basidiospores. Within this genus, Entoloma sect. Madida, corresponding to the Prunuloides lineage in recent infrageneric treatments, includes several morphologically similar taxa related to the E. bloxamii–prunuloides complex. However, this lineage remains poorly documented from subtropical eastern China. In this study, we examined Entoloma collections from the Huangshan region of Anhui Province, China, using macromorphological observations, micromorphological characters, scanning electron microscopy (SEM) of basidiospores, and multilocus phylogenetic analyses based on ITS, LSU and rpb2. We recognised two independent and well-supported species-level lineages, described here as Entoloma theobrunneum and E. ochrorubrum. Entoloma theobrunneum is phylogenetically close to E. corneri but differs in its smoky grey to tea-brown pileus, snakeskin-like stipe pattern, higher basidiospore Q values, larger basidia, and the presence of pleurocystidia and caulocystidia. Entoloma ochrorubrum is associated with taxa of the E. bloxamii complex but is distinguished by its darker iron-red to ochre-brown pileus, blackish-brown central papilla, cracking pileus margin, longitudinally fibrillose stipe, higher basidiospore Q values, and basidia with granular contents. SEM observations are provided only as supplementary documentation of the three-dimensional architecture of basidiospores. These findings add two phylogenetically supported Chinese species to the current framework of E. sect. Madida, help fill a regional documentation gap in subtropical eastern China, and provide additional East Asian data relevant to future evaluation of the current infrageneric framework of Entoloma.