Xerocomellus perezmorenoi Ayala-Vásquez & M. Martínez-Reyes, 2023

Martínez-Reyes, Magdalena, Carrera-Martínez, Anaitzi, Fuente, Javier Isaac De La, Ríos-García, Uzziel, Ortiz-Lopez, Ivette & Ayala-Vásquez, Olivia, 2023, Xerocomellus perezmorenoi (Boletaceae, Boletales), a new edible species from Mexico, Phytotaxa 584 (2), pp. 104-114 : 109-112

Xerocomellus perezmorenoi Ayala-Vásquez & M. Martínez-Reyes , sp. nov.

( Fig. 2 , 3 )

Mycobank no. 841765. GenBank no. OK350679 (ITS), OK350681 (LSU).

Type: — MEXICO. Tlaxcala State, Nanacamilpa Municipality, San Felipe Hidalgo Town, Piedra Canteada place, 0539120 W, 2151906 N, 3285 m. a. s. l., 23 August 2021, Ayala-Vásquez ( MEXU-HO 30410 ).

Diagnosis: — Xerocomellus perezmorenoi is characterized by small basidiomata; pileus brown at the center and cream with pink to purple tones at the margin, almost blackish at the center when young, black-brown when at mature, pores lilac, peach to salmon when young, yellow citrine at mature; basidiospores (12–) 15–16 (–17) × 4–5 (–6) µm, ellipsoid-fusoid.

Description: — Basidiomata pileate-stipitate, epigeous. Pileus 14–50 mm diam, broadly convex when young, planeconvex at maturity, pink, cream to purple tones (14A3) at the margin, brown (5F5) at the center, almost blackish at the center when young, dark-brown (5F8) when at mature, pileus surface tomentose to areolate when young, with a cracking brown (5F4) to dark-brown (5F8) showing yellowish (4A5) flesh at mature, sterile margin incurvated. Hymenophore annexed, pores 0.3–1.0 mm diameter, irregular, circular to angular pale purplish (14A3) when immature, pale pink to salmon when young, yellow citrine (4A8) some pastel red (9A4–9A5) tones in the terminal pores of the apex of the stipe at maturity, when cut bruising pale-green (28A3) to olivaceus (30D5). Tubes 3–9 mm in length, purplish (14A3) when young, turning yellow (4A8) when mature, when bruising or when bruising or cut pale green (28A3). Context 2–7 mm thick, whitish to vinaceous (12D8) at immature, in a juvenile and mature stage with whitish, to the cut after two minutes is stained bluish-green (28A4); the context of the stipe, brown (5F4) at the base at immature, pale yellow (4A4) some olive-brown (30E8) at mature, the rest of the context whitish to pale yellow (4A4), to the cut it is stained bluish green (28A4). Stipe 28–63 × 7–8 mm, attenuated, subclavate to cylindrical; yellowish (4A5) at the apical, the rest of the salmon pink, pastel red (9A4–9A5), with purplish (14A4) tones when at immature, surface tomentose with appearance pulverulent at base, whitish to yellowish (4A3) mycelium. Odor and taste indistinct. Chemical reaction when applying KOH 10% on the surface pileus dark-red (9E8) to vinaceus (12D8), surface stipe ochraceous yellow(30C8), reddish tones to amber (5F8) hymenium and context.

Basidiospores (12–) 15–16 (–17) × 4–5 (–6) µm, [Q = 2.4 ± 0.6] fusoid to subcylindrical, to cylindrical inside view, with or without distinctly suprahilar depression, smooth, yellowish-brown, multigutulate, thick wall 0.8–1.0 µm. Basidia 33–47 × 5–6 µm, clavate, with lipid content, hyaline to pale yellow, tetrasporic, sterigmata 3.4–5.0 × 1–2 µm. Pleurocystidia 35–60 (–68) × 5–6 µm, brown-yellowish, golden, some hyaline in KOH, obclavate, cylindrical, subfusoid, subclavate with visible granular content in Melzer. Cheilocystidia 50–55 × 9–11 µm, ventricose-fusoid, thick-walled, yellowish-brown in KOH, golden yellow in Melzer solution. Hymenophoral trama boletoid; with central cylindrical hyphae 7–11 µm hyaline to pale yellow, lateral hyphae 4–7 µm, cylindrical. Pileipellis 150–200 mm thick, trichoderm, with cylindrical, subfusoid, subclavate terminal cells, thick-walled yellow-brown in KOH, golden to yellow-brown in Melzer solution. Caulocystidia 13–23 × 4–8 (–12) µm, clavate, very scarce, mamillated to ovoid; caulobasidioles very scarce 23–27 × 8–10 µm, subclavate, hyaline in KOH to pale yellow, thin wall.

Etymology: —Dedicated to the eminent Mexican mycologist Prof. Jesús Pérez Moreno who is a pioneer in biotechnology of ectomycorrhizal fungi with biocultural importance in Mexico mainly Boletales and Agaricales , with more than 30 years of experience.

Distribution: —Epigeous, in mixed coniferous forest under Abies religiosa . Recorded from the Mexican state of Tlaxcala, State of Mexico and Puebla.

Additional material examined: — MEXICO. Tlaxcala State, Nanacamilpa Municipality, San Felipe Hidalgo Town, Piedra Canteada Place , 0539151W, 2151881N, 3286 m. a. s. l., 15 September 2021, Ayala-Vásquez, Ríos-García ( MEXU-HO 30411 ) ; Piedra Canteada Place , 0539151 W, 2151881N, 3286 m. a. s. l., 27 September 2021, AyalaVásquez ( MEXU-HO 30450 ) , Estado de Mexico State, Ocuilan Municipality, San Juan Atzingo Town, mixed forest Place , 18 September 2021, Martínez-Reyes M, ( MEXU-HO 30412 ) , Puebla, Santa Rita Tlahuapan Municipality, San Juan Cuauhtémoc Town , 28 September 2021, Ayala-Vásquez, O. Martínez-Reyes, ( MEXU-HO 30449 ) .

Dichotomous key of species the genus Xerocomellus described in Mexico

1a Basidiomata epigeous to aberrant................................................................................................................................... X. carmeniae

1b Basidiomata only epigeous.................................................................................................................................................................2

2a pileus pink-red to vinaceous red, rosy red or brick-red, associated with Quercus agrifolia .......................................... X. dryophilus

2b Pileus typically pale brown, brown, black brown to black.................................................................................................................3

3a Pores lilac, peach to salmon when young, yellow citrine at mature........................................................................... X. perezmorenoi

3b Pores yellow to yellow-olivaceous................................................................................................................................... X. truncatus

Figures

FIGURE 2. Xerocomellus perezmorenoi. A (MEXU-HO 30411paratype), D (MEXU 30410-type). context of basidiomata; B (MEXU 30410-type), E (MEXU 30411 paratype). hymenophore; C surface of pileus (MEXU 30411 paratype); F basidiomata (MEXU 30412 paratype). Scale bars: 10 mm.

FIGURE 3. A basidiospores; B pleurocystidia; C basidia; D pileipellis; E cheilocystidia; F pileipellis. Scale bars: 10 µm. (MEXU 30410- type).