Pseudobaeosporoideae, a new subfamily within the Tricholomataceae for the genus Pseudobaeospora (Agaricales, Tricholomatineae) based on morphological and molecular inference

Abstract

Based on molecular and morphological evidence the new subfamily Pseudobaeosporoideae of the Tricholomataceae is established within the Tricholomatineae for accommodating the unique features of Pseudobaeospora such as gymnocarpic mycenoid/collybioid habit, small-sized spores with thick and dextrinoid wall, and presence of crassobasidia. Twenty-six Pseudobaeospora collections corresponding to eleven species (five types) were newly sequenced. Collections morphologically attributable to P.oligophylla (type of the genus) or to P.pillodii are here sequenced for the first time: accordingly, P.oligophylla is considered as a posterior synonym of P.pillodii. Quélet's original plate is selected as a lectotype for Collybiapillodii and a French collection as its epitype collection. Pseudobaeosporadeceptiva is described as a new species from Italy very close to P.pillodii from which it differs mainly by bigger spores and SSU and LSU rDNA sequences. The presence of P.pyrifera in Italy is documented for the first time and P.mutabilis is reduced to its later synonym. A neotype is established for P.jamonii which is here proved to be an independent species. Finally, a critical review of the characters used for interspecific distinctions in Pseudobaeospora was provided.

Keywords: Agaricomycetes; Basidiomycota; Pseudobaeospora; Tricholomataceae; Tricholomatoid clade; taxonomy.

Figure 1.

Bayesian inference phylogram built with nucleotide sequence data of four loci (nrLSU, nrSSU, RPB2-exons and TEF1-exons) of the main lineages inside the suborder Tricholomatineae of the order Agaricales, rooted with Suilluspictus (Boletales), Ampulloclitocybeclavipes and Pseudoarmillariellaectypoides (Hygrophorineae, Agaricales) as outgroups. Nodes were annotated with Bayesian PP (left) and ML BP (right) values, with the significance threshold considered as Bayesian PP ≥ 0.95 and/or ML BP ≥ 70%. Subsignificant support values were annotated in parentheses. All family-level clades, except for Tricholomataceae, were collapsed. Boldface names represent samples sequenced for this study.

Figure 2.

Mid-point rooted Bayesian phylogeny (nrITS, nrLSU, nrSSU, RPB2-exons) of the Tricholomataceae s.s. Nodes were annotated with Bayesian PP (left) and ML BP (right) values, with the significance threshold considered as Bayesian PP ≥ 0.95 and/or ML BP ≥ 70%. Subsignificant support values were annotated in parentheses. Boldface names represent samples sequenced for this study.

Figure 3.

Bayesian inference phylogram built with ITS nucleotide sequence of Pseudobaeospora, rooted with Tricholomainamoenum (Tricholomataceae) as outgroup. Nodes were annotated with Bayesian PP (left) and ML BP (right) values, with the significance threshold considered as Bayesian PP ≥ 0.95 and/or ML BP ≥ 70%. Subsignificant support values were annotated in parentheses. Boldface names represent samples sequenced for this study. Clades are named following Craig et al. (2023).

Figure 4.

Basidiomes of some sequenced Pseudobaeospora collections. aP.calcarea (LIP PAM06090111-FR2013078); bP.cyanea (GDOR M3986); cP.laguncularisvar.denudata (LIP PAM99101004-FR2013079); dP.pillodii (KRAM F-53314); eP.terrayi (SAV-F:3317, holotype); fP.terrayi (SAV-F:20813). Lectotype of. C.pillodii; g Quélet’s original plate, pl. XV, fig. 4. Photos: a, c by P.A. Moreau; b by D. Gisotti; d by A. Ronikier; e, f by S. Jančovičová.

Figure 5.

Pseudobaeosporapillodii, microscopic features. Pileipellis. a–c (KRAM F-53298); d (KRAM F-53314); e, f (LE 254346); g, h (O-F:258872); a–h in ammoniacal Congo red. Scale bars: 10 µm (a–c); 20 µm (e–h). Photos by L. Setti.

Figure 6.

Pseudobaeosporapillodii, microscopic features. Stipitipellis. a (KRAM F-53298); b (KRAM F-53314). Spores; c (KRAM F-53298); d (KRAM F-53314); e (LE 254346); f (O-F:258872); a–f in ammoniacal Congo red. Scale bars: 10 µm (a); 20 µm (b); 5 µm (c–f). Photos by L. Setti.

Figure 7.

Pseudobaeosporadeceptiva (MCVE:15315, holotype). a Basidiomes; b–d pileipellis; e spores; f caulocystidia; b–f in ammoniacal Congo red. Scale bars: 20 µm (b–d); 5 µm (e); 10 µm (f). Photos by L. Setti.

Figure 8.

Pseudobaeosporapyrifera. Basidiomes. a AMB 18729; b AMB 18730; c SAV-F:3518 (holotype of P.mutabilis); d–f SAV-F:3524. Photos: a, b by G. Consiglio; c–f by S. Jančovičová.

Figure 9.

Pseudobaeosporapyrifera, microscopic features (AMB 18730). a, b Pileipellis; c crassobasidia; d hymenophoral trama; e, f cheilocystidia; g caulocystidia; h spores; a, b, e, g in ammoniacal Congo red; c, d, f, h in L4. Scale bars: 20 µm (a, d); 5 µm (b, c, e–h). Photos by L. Setti.

Figure 10.

Pseudobaeosporapyrifera, microscopic features (collections named as P.mutabilis). Pileipellis. a SAV-F:20580; b SAV-F:20589; c SAV-F:3524. Cheilocystidia; d SAV-F:20580; e SAV-F:20589; f SAV-F:3524. Caulocystidia; g SAV-F:20580; h SAV-F:20589; i SAV-F:3524. Spores; j SAV-F:20580; k SAV-F:20589. l SAV-F:3524; a–l in ammoniacal Congo red. Scale bars: 10 µm (a–f, h–i); 20 µm (g). j–l. Photos by L. Setti.

Figure 11.

Pseudobaeosporajamonii, microscopic features (neotype, AQUI:10322). a–c Pileipellis; d, e cheilocystidia; f spores; a–f in ammoniacal Congo red. Scale bars: 20 µm (a); 10 µm (b–e); 5 µm (f). Photos by L. Setti.

Figure 12.

Pseudobaeosporacelluloderma, microscopic features (UPS-F 623041). a–c Pileipellis; d cheilocystidia; e crassobasidia; f spores; a–f in ammoniacal Congo red. Scale bars: 10 µm (a, b, d); 15 µm (c); 5 µm (e, f). Photos by L. Setti.

Figure 13.

Pseudobaeosporacyanea, microscopic features (GDOR M3986). a, b Pileipellis; c hymenium (basidia and cheilocystidia); d basidia; e spores; f hymenophoral trama; a–f in ammoniacal Congo red. Scale bars: 20 µm (a, b, f); 10 µm (c); 5 µm (d, e). Photos by L. Setti.