Pseudobaeospora jamonii Bas, Lalli & Lonati

Vizzini, Alfredo, Consiglio, Giovanni, Adamčíková, Katarína, Setti, Ledo & Adamčík, Slavomír, 2025, Pseudobaeosporoideae, a new subfamily within the Tricholomataceae for the genus Pseudobaeospora (Agaricales, Tricholomatineae) based on morphological and molecular inference, IMA Fungus 16, pp. e 144994-e 144994 : e144994-

Pseudobaeospora jamonii Bas, Lalli & Lonati , Micol. Veg. Medit. 17 (1): 32 (2002)

Fig. 11

– P. pillodii (forma) auct. non (Quél.) Wasser: Jamoni & Bon, Bull, trimest. Feder. mycol. Dauphine-Savoie 143: 12 (1996).

Holotype.

(missing): ITALY • Piemonte, Monte Rosa, Alagna, bassa valle dell’Orto , about 1300 m, 3 September 1994, leg. P. G. Jamoni (Fungarium Jamoni).

Neotype.

(designated here, MBT 10024683 ): Italy, Abruzzo, San Pietro, Isola del Gran Sasso (TE), 13 September 1995, leg. G. Lalli & G. Lonati ( AQUI: 10322).

Selected iconography.

Jamoni and Bon (1996: photo on cover, as form of P. pillodii ), Bas et al. (2002: Fig. 1 ).

Selected descriptions.

Jamoni and Bon (1996: 12–13), Bas (2003: 177–179), Bas et al. (2002: 32–35).

Description.

Spores (2.9 –) 3.2–3.5 – 3.8 (– 4.5) × (2.6 –) 2.9–3.1 – 3.3 (– 3.6) μm (64 / 1 / 1), Q = (0.97 –) 1.04–1.15 – 1.25 (– 1.52), V = (11.3 –) 14.4–17.8 – 21.2 (– 28.2) μm 3, globose to subglobose, wall up to a 0.8 µm thick, smooth, colorless in L 4: hilar appendix prominent, 0.8–1 µm long. Basidia 16–18 × 4.0–5.0 µm, tetrasporic, subclavate to cylindrical, sterigmata up to 4 µm long; crassobasidia very rare. Hymenophoral trama regular to subregular, consisting of up to 8 µm wide hyphae, colorless in L 4. Cheilocystidia mainly clavate, hardly differentiated from the basidia, but also elongate clavate to (sub) lageniform, cylindrical or irregularly shaped, 25–32 × 8.3–10.3 µm. Pleurocistidia absent. Pileipellis: turning greenish brownish to pale green in KOH; suprapellis formed by broadly ellipsoid to broadly cylindrical elements, often emerging and then pileocystidia-like, sometimes slightly swollen, with rounded apex, smooth, up to 9 µm wide; subpellis slightly aeriferous, consisting of slightly gelatinized, smooth, subglobose to broadly cylindrical, up to 16 µm wide hyphae; pigments light brown, mainly intracellular. Stipitipellis composed of cylindrical, densely septate, up to 3 µm wide, longitudinal and parallel hyphae. Stipititrama of up to 10–12 µm wide hyphae, greenish in KOH. Caulocystidia at stipe apex scattered or clustered, 10–50 × 4–10 pm, filiform to narrowly clavate, subcylindrical or slender and somewhat irregular. Clamp-connections present mainly on the suprapellis hyphae and at the basidia and cheilocystidia bases.

Material examined.

ITALY • Abruzzo, San Pietro, Isola del Gran Sasso (TE), 13 Sept. 1995, G. Lalli & G. Lonati ( AQUI: 10322, neotype) .

Notes.

Both the holotype (private fungarium, Jamoni) and the isotype collections (L) are missing (Pier Giovanni Jamoni, pers. comm. and Nicolien Sol, Leiden, pers. comm., respectively). The Italian collection studied here ( AQUI: 10322) was included as part of studied material (paratype) in the protologue ( Bas et al. 2002) and is selected as the neotype here.

This taxon was first time provisionally described as a peculiar form of P. pillodii with clamp-connections, cheilocystidia and tetrasporic basidia, from Alpine areas in Piedmont (northwestern Italy) in mixed forests ( Alnus incana , Acer , Fraxinus , Fagus , Corylus , and Picea abies ) often near Buxus ( Jamoni and Bon 1996) . It was then formally described as a new species ( Bas et al. 2002) based on the previously cited Piedmont collections and a new collection from Abruzzi (Central Italy) and included by Bas (2003) in his European monographic work on the genus.

Both in the multigene (Fig. 2 ) and ITS analyses (Fig. 3 ), the neotype collection of P. jamonii is recovered as an independent species. In the multigene analysis, it is sister to a clade formed by P. wipapatiae and P. pyrifera (including P. mutabilis ); in the ITS analysis, it is sister to a clade consisting of four environmental sequences of an undescribed probably new species from Portugal. Similarities and differences between this species and P. pyrifera are discussed above.

Figures

Figure 1. Bayesian inference phylogram built with nucleotide sequence data of four loci (nrLSU, nrSSU, RPB 2 - exons and TEF 1 - exons) of the main lineages inside the suborder Tricholomatineae of the order Agaricales, rooted with Suillus pictus (Boletales), Ampulloclitocybe clavipes and Pseudoarmillariella ectypoides (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, RPB 2 - 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 Tricholoma inamoenum (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 11. Pseudobaeospora jamonii, 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.