<p><strong>Two new species of <em>Micropsalliota</em> (Agaricaceae/Agaricales) from Thailand</strong></p>

Abstract

Micropsalliota embraces approximately 70 species which are mainly distributed in tropical and subtropical areas. In this study, two new species named Micropsalliota albella and M. purpureobrunneola are introduced from northern Thailand. Phylogenetic analyses based on ITS and LSU data shows their placement in Micropsalliota in two distinct lineages. Micropsalliota albella is characterized by the white, tiny basidiomes and utriform cheilocystidia. Micropsalliota purpureobrunneola is characterized by the pileus finely covered with purple to brownish-purple scales, oblong basidiospores and narrowly clavate cheilocystidia. Descriptions, colour photographs and illustrations of both new species are presented.

Taxonomy and multi-gene phylogeny of Micropsalliota (Agaricales, Agaricaceae) with description of six new species from China

“…The results of our phylogenetic analysis are to some extent consistent with previous studies based on ITS and LSU sequences (Zhao et al, 2010 ; He et al, 2020 ; Li et al, 2021 ; Al-Kharousi et al, 2022 ), but we were able to resolve more subclades, and the support values for some clades and subclades were higher. Major clades were strongly to weakly supported, but were difficult to morphologically characterize.…”

“…and Leelav., and M. pusillissima R. L. Zhao, Desjardin, Soytong and K. D. Hyde all have tiny basidiomata (pileus 5 mm in diameter or less) that are similar to M. pseudodelicatula . These species can be distinguished as follows: basidiospores of M. alba are larger, up to 5.8–6.6 × 3.3–3.6 μm (Heinemann and Flower, 1983 ); M. albella has narrowly utriform to utriform cheilocystidia, some of which are slightly subcapitate (He et al, 2020 ); cheilocystidia of M . albosericea are smaller (18–30 × 6.0–11 μm) and clavate to ventricose-capitate or subcapitate, without obviously elongated neck (Zhao et al, 2010 ); M. minor has forked cheilocystidia (this paper); M. pulverulenta has pleurocystidia (Heinemann and Leelavathy, 1991 ); M. pusillissima has smaller basidiomata (1.0–3.0 mm) and possesses broadly ventricose-capitate cheilocystidia without an obviously elongated neck (Zhao et al, 2010 ).…”

“…Some species have small basidiomata and a colored pileus but can be separated as follows: M. allantoidea has grayish brown scaly pileus, utriform, lageniform, or tiibiform capitate or subcapitate cheilocystidia (Zhao et al, 2010 ); M. atropurpurea Heinem., M. cymbispora Heinem. and Little Flower, and M. pseudovolvulata have smaller basidiospores averaging less than 5.5 μm long (Heinemann and Flower, 1983 ; Heinemann, 1988 ; Zhao et al, 2010 ); M. cardinalis and M. purpureobrunneola have purple to brownish purple scales and different cheilocystidia (Heinemann, 1989 ; He et al, 2020 ); M. endophaea Heinem., M. megaspora , and M. roseipes have larger basidiospores that are longer than 6.5 μm on average (Heinemann, 1988 ; Zhao et al, 2010 ); M. malabarensis Heinem. and Little Flower and M. subalpina Guzm.-Dáv.…”

“…Micropsalliota arginea, M. cinnamomeopallida, M. plumeria , and M. pseudoarginea resemble M. tenuipes but have smaller basidiospores (< 5.5 μm long) (Pegler and Rayner, 1969 ; Heinemann, 1980 , 1988 ; Heinemann and Leelavathy, 1991 ; Zhao et al, 2010 ). In the phylogenetic tree, M. tenuipes groups together with M. albella , but the latter has smaller basidiomata (a pileus 2.0–5.0 mm in diameter) and basidiospores shorter than 5.5 μm (He et al, 2020 ).…”

“…Micropsalliota is not a very species-rich genus: only 79 names (62 species and five varieties), including synonyms, were listed in Index Fungorum (www.indexfungorum.org). Species of Micropsalliota are mainly distributed in tropical and subtropical Africa, America, and Asia (Heinemann, 1977 , 1980 , 1983 , 1988 , 1989 ; Heinemann and Flower, 1983 ; Heinemann and Leelavathy, 1991 ; Guzmán-Dávalos, 1992 ; Guzmán-Dávalos and Heinemann, 1994 ; Zhao et al, 2010 ; Chen et al, 2016 ; Parra et al, 2016 ; He et al, 2020 ; Crous et al, 2021 ; Al-Kharousi et al, 2022 ). Beginning with the discovery of M. pseudoglobocystis Li Wei and R. L. Zhao, 13 species, of which four are new, have been reported in China (Li et al, 2015 , 2021 ; Wei et al, 2015 ; Wang et al, 2017 ; Chen et al, 2019 ; Sun et al, 2020 ; Liu et al, 2021 ).…”