Type studies on two Paxillus species (Paxillaceae, Boletales) described from China

Abstract

Types and recently collected samples of two Paxillus species namely P. rhytidophyllus and P. yunnanensis, originally described from southwestern China, were critically restudied based on morphology and molecular phylogenetic data of DNA sequences from the large subunit of the nuclear ribosomal RNA (nrLSU), the nuclear ribosomal internal transcribed spacer (ITS), and the translation elongation factor 1-α (tef1-α). The results showed that these two species belong to Boletinellus and Tricholomopsis, respectively. Thus, two new combinations, Boletinellus rhytidophyllus and Tricholomopsis yunnanensis are proposed. Boletinellus rhytidophyllus is characterized by a deeply decurrent and shallow hymenophore which is poroid-lamellate to alveolate, slightly thick-walled (0.6–1 μm) basidiospores, occasionally 2- to 4-spored basidia, rare or infrequent hymenial cystidia, and a trichodermal pileipellis. Tricholomopsis yunnanensis is characterized by a convex pileus densely covered by red-violet to red-brown fibrillose squamules, a yellowish stipe sparsely covered with red to red-brown fibrillose squamules, subglobose to broadly ellipsoid basidiospores, prominent large cheilocystidia measuring 60–195 × 11–39 μm, and a palisadic pileipellis. New descriptions and line drawings of these two species and their comparisons with allied taxa are presented.

Phylogenetic and taxonomic updates of Agaricales , with an emphasis on Tricholomopsis

“…Phylogenetic analysis indicated that T. yunnanensis and T. galeata are conspecific. Although Mao et al ( 2021 ) did not find any pleurocystidia in T. galeata and Liu et al ( 2022 ) regarded the pileipellis as palisadoderm, we observed the presence of pleurocystidia and regarded the pileipellis as a cutis with transition to a trichoderm in T. yunnanensis .…”

“…Notes : Tricholomopsis yunnanensis was first described in southwestern China as Paxillus yunnanensis by Zang and Zeng ( 1978 ). The type was restudied by Liu et al ( 2022 ), who placed it into Tricholomopsis as T. yunnanensis . Phylogenetic analysis indicated that T. yunnanensis and T. galeata are conspecific.…”

Genus Paxillus: A new record for Pakistan based ITS-nrDNA marker and phylogenetic studies

“…It is found across the Northern Hemisphere mostly in wetlands and often forms symbiotic relationships with different types of plants, such as hardwood and coniferous trees. These mushrooms are versatile, thriving in various ecosystems, even in degraded or contaminated areas (Cagigal and Sánchez, 2017;Liu et al 2022).…”

“…Few taxa of this genus have biochemical properties and play a bene cial role in agroecology i.e., nutrient cycling, aiding host plants in acquiring essential nutrients and enhancing their tolerance to heavy metals (Sayyed and Hussain 2020). Up until now, seventy one (71) different species have been identi ed and described as belonging to the Paxillus genus worldwide (Liu et al 2022, https://www.indexfungorum.org/names/names.asp). In Pakistan, this genus seems new as no report of Paxillus has been found in previously published literature.…”