Tricholoma colposii J. Pérez-Moreno, M. Martínez-Reyes M. & O. Ayala-Vásquez O., 2022

Ayala-Vásquez, Olivia, Fuente, Magdalena Martínez-Reyes Javier Isaac De La, Martínez-González, César Ramiro, Armas, Leticia Flores, Santiago, Faustino Hernández- & Pérez-Moreno, Jesús, 2022, Tricholoma colposii (Tricholomataceae, Basidiomycota), a new edible species of matsutake fungi from Eastern Mexico with economic and biocultural importance, Phytotaxa 542 (1), pp. 24-34 : 27-31

Tricholoma colposii J. Pérez-Moreno, M. Martínez-Reyes M. & O. Ayala-Vásquez O. sp. nov. Figure 2 .

Mycobank no. MB843068; GenBank. OM732329

Diagnosis: —It is characterized by middle size basidiomata, with orange brown to brown pileus and stipe, squamose when young and with appressed scales in maturity, cylindric, fibrillous to scaly stipe, with globose to ellipsoid (4.5–)5–6 (–7) × (3–) 4–5 (–6) μm smooth spores, sweet fruit odor and raw green bean flavour sporomes. It associated with Pinus teocote in eastern Mexico forests. The macro- and micromorphological characters in conjuntion with the nrITSbased phylogenetic analysis support the proposal of this new species of matsutake fungus.

Holotype: — MEXICO. Veracruz state, Parque Nacional Cofre de Perote, 1 September 2021, Flores Armas L., ( CP161 , MEXU 30413 ). GenBank [ITS]: OM 732326 .

Etymology: —“ colposii ” refers to Colegio de Postgraduados, commonly abbreviated as “Colpos”, which is an Agricultural teaching and research institution in Mexico which has funded research related with edible ectomycorrhizal mushrooms during more than 30 years.

Description: —Pileus 31–85 mm in diameter, broadly convex, convex to plane with a slight central depression at maturity, orange-brown (6C6) to brown (6D6‒6D7), showing some beige to whitish tones, surface light brown, orangebrown radial, triangular to circular fibrils, central fibril slightly darker than margin, dry, margin fully adherent to partial veil when young, fibrillose texture fully covering hymenium, torn, with remnants of the veil at maturity. Hymenophore adhered, lamellae close, sinuate, whitish when young, beige when mature with pale brown tones. Context 6–8 mm thick, whitish, solid, without change in color when cut. Stipe 25–103 × 15–22 mm, cylindrical to subclavate, surface with fibrils covering the base to the middle, dry, with a satiny appearance orange-brown (6C6) to brown (6D6-6D7), revealing some beige to whitish shades, completely white apex, very marked irregular ring in the middle part. Basal mycelium whitish. Odor sweet, fruity. Taste raw green bean flavor ( Phaseolus vulgaris L.).

Basidiospores (4.5–)5–6 (–7) × (3–) 4–5 (–6) μm, Q=1.1–1.8 μm, (n= 50), ellipsoid to subglobose, hyaline in KOH, nonamyloid, pale brown in Melzer, thick-walled, guttulate with or without visible suprahilar depression. Crassospores observed, thick-walled. Basidia 32– 40 (–48) × (6–) 7–8 µm, 4-sterigmata, narrowly clavate, long sterigmata 3–4× 1– 1.2 μm, with granular content. Basidioles 30–35× 7–8 μm. Hymenial trama parallel, composed of cylindrical hyphae (3–) 4–10 μm, hyaline in KOH, thick-walled 1 μm. Stipitipellis formed by tubular hyphae 5–8 μm, thick-walled 1–1.2 μm hyaline in KOH. Pileipellis formed by a trichoderm of intertwined hyphae in a radial arrangement, terminal hyphae 20–58 (–75) × (6–) 7–8 µm, cylindrical, clavate, subglobose to pyriform, hyaline to pale brown in KOH, brown in melzer, thick-walled.

Notes:— Tricholoma colposii differs from its closest relative T. mesoamericanum by the white and smooth pileus surface in young specimens and a stipe with yellow or brown spots all over, and basidiospores 4.5–6.5 × 3.5–4.5 µm, while T. colposii has orange-brown basidiomata, with scales or fibrils from the immature stage, fibrillous to scaly cylindric equal stipe, and basidiospores 5–6 (–7) × 4–5 (–6) μm. Molecularly both species are monophyletic but located in different clades clearly separated ( Fig. 1 ).

Habitat, habit, distribution: —Solitary to disperse. Known from the Cofre de Perote National Park, from Mexico, growing under Pinus teocote forests, from the end of August to the end of October, having a late short at the end of the rainy season phenology.

Specimens examined: — MEXICO, Veracruz state, Parque Nacional Cofre de Perote National Park, 15 August 2018, L. Flores-Armas (Colpos 25), 25 August 2021, Mycoredes, ( CPM162 , MEXU 30414 ) , 2 September 2021, Mycoredes, ( CPM163 , MEXU 30415 ) . MEXICO, Parque Nacional Cofre de Perote , 2 October 2021, Mycoredes, ( CP45 , MEXU 30416 ) .

Figures

FIGURE 1. Phylogram of Bayesian inference (BI) tree from the ITS sequence data of 44 specimens. Tricholoma bakamatsutake was used as the outgroup. The values above branches represent Bayesian posterior probabilities (PP, left) and bootstrap values (LP, right) for maximum likelihood, respectively. The scale bar represents the expected number of nucleotide substitutions per site. Sequences obtained from this study are in red. Type species are in bold.

FIGURE 2. Tricholoma colposii (MEXU 30413, holotype). A. Basidiomata in different stages. B. Basidia and basidiospores. C. Close-up of orange-brown to brown fibrillose to scaly pileipellis. D. Grade 1 basidiomata which are the most expensive. E. Basidiomata in a Pinus teocote forest, its natural habitat. Scale Bar: A and E= 100 mm, B = 10µm; C and D= 50 mm.