Xylaria sanmartinii Raymundo, Sánchez-Flores, Mart.-Pineda & R. Valenz., 2025

Raymundo, Tania, Sánchez-Flores, Marcos, Martínez-Pineda, Michelle, Martínez-González, César Ramiro, Ramírez-Martínez, Julio Cesar, Luna-Vega, Isolda & Valenzuela, Ricardo, 2025, Xylaria sanmartinii (Ascomycota, Sordariomycetes), a new species from the Mexican tropical montane cloud forest, Phytotaxa 711 (1), pp. 61-71 : 65-68

Xylaria sanmartinii Raymundo, Sánchez-Flores, Mart.-Pineda & R. Valenz. sp. nov. Figs 2 , 3 .

MycoBank: MB845004

Etymology:— In honour of Felipe San Martín, specialist of Xylariales in México.

Type:— MÉXICO. Hidalgo: Sierra Madre Oriental, municipality of Acaxochitlán, Acaxochitlán, 20°14’12”N 98°09’39”W, 1979 m, 23 September 2016, R. Valenzuela 16907 (Holotype: ENCB).

GenBank: ITS: PV793161; TUB: PV797259; RPB2: PV797260

Diagnosis:— Xylaria sanmartinii is characterized by its red to orange-reddish when mature and red brick to deep magenta in dry specimens on the stromatal surface, its larger ascospores 22–28 × 10–14 µm, and its habitat on dead wood in the Mexican tropical montane cloud forest.

Description:—Stromata 30–110 mm long, 2–5 mm diameter, unbranched to bifurcate, gregarious, cylindrical, with a mucronate sterile apex, stromatal surface when young ruby greyish (12E7), when mature orange red (8A7) to tomato red (8C8), to deep magenta (14E8) in dry specimens; coloured granules present in the peeling outer layer are red in water and turn deep blue (20D8) by adding 10% KOH, and dark ruby (12F8) in Melzer's reagent; fertile stromata 9–50 × 2–5 mm, with conspicuous perithecial ostioles in the surface; stipe 10–50 × 1–3 mm, filiform, pastel red (8A4), brownish red (8C7) to black with age; perithecia immersed, 477–820 × 338–500 µm, subglobose to ovoid, with wall 36–50 µm thick, black, ostioles papillate; paraphyses up to 2 µm in diameter, filiform, hyaline; asci 160–210 × 7–9 µm, cylindrical, long stipitate, stipes 40–60 × 1.5–2 µm, eight-spored, hyaline, spore-bearing part 117–138 × 7–9 µm, with apical ring bluing in Melzer's iodine reagent, hat-shaped, 3.2–4.2 × 1.6–2.4 µm; ascospores (19–)22–28 × 10–14 µm, ellipsoid-inequilateral, smooth, brown to dark brown, thin-walled, with narrowly rounded ends, with conspicuous straight germ slit on the ventral side.

Culture morphology:— Growth rate 0.5 cm /week. Initially, the mycelium is white, cottony, and zoned in the center. After 20 days, it grows radially towards the edge with abundant aerial mycelium. The reverse mostly remains white for up to four weeks, finally turning brown and showing exudates and melanic pigments.

Habit and habitat:— Growing gregariously on decaying angiosperm wood, causing soft rot. Distribution:— Mexican TMCF ( Fig. 4 ).

Notes:— Xylaria sanmartinii is characterized by red to orange-reddish, red brick colours and large ascospores. This species grows on dead wood in the Mexican TMCF. It is similar to X. violaceorosea J. Fourn., A. Román, Balda & E. Rubio , by its red to purple stromata in dry specimens, but the latter has smaller spores (14–)15.8–16.3(–18) × (5–)5.9–6.1(–17) µm. In addition, X. violaceorosea grows on dead corticated twigs and branchlets of Castanea sativa and Quercus sp. in Spain ( Fournier et al. 2014). X. violaceopannosa Starb has smaller spores (10–11 × 5–5.5 µm), and the type is from Asunción, Paraguay (Starbäck 1901). X. corniculata Sacc. and X. scruposa (Fr.) Fr. are similar species in the size of spores (16.5–18 × 6–7 µm; 18–21 × 6–7 µm, respectively); however, they differ by having a spiral germ slit and black stromata ( San Martín & Rogers 1989). X. vinosa J. Forn., Y. M & Lechant is similar to X. sanmartinii in the apiculate apex and the red colour of the stromata, but presents spores of 9.3–11 × 3.7–4.8 µm. Phylogenetically, X. sanmartinii is related to X. crozonensis P. Leroy & Mornand , but the latter has sessile, pulvinate, dark brown to black stromata, and smaller ascospores (11.3–)17(–19.9) × (7.2–)8.8(–9.7) µm ( Rubio et al. 2016). X. brunneovinosa Y.M. Ju & H.M. Hsieh is a morphologically similar species, with similar reddish and vinaceous colours, but it produces smaller ascospores (5.8–)6–7(–7.5) × 4–5 µm ( Ma et al. 2013).

Material examined:— MÉXICO. Hidalgo: municipality of Acaxochitlán, Acaxochitlán , 20°14'12"N 98°09'39"W, alt. 1979 m, 23 September 2016, T. Raymundo 6272 ( ENCB), B. Pérez-Rosas 28 ( ENCB), A. Cobos-Villagrán 429 ( ENCB) ; Michoacán, municipality Nuevo San Juan Parangaricutiro , Barranca de la Culebra, 19°21'51"N 102°11'32"W, alt. 2220 m, 13 August 2018, T. Raymundo 7830 ( ENCB) ; Nayarit, municipality of Xalisco, Sierra San Juan , La Noria, 21°29'39"N 104°59'31"W, alt. 1490 m, 30 September 2018, M. Sánchez 1426, 1429 ( ENCB) ; Oaxaca, municipality of Huautla de Jiménez, Huautla de Jiménez , 18°7'21.66"N 96°50'5.18"W, 24 June 1978 G. Guzmán 18424 ( ENCB) ; Puebla, municipality of Honey, Cascadas Arcoiris , 20°15'32"N 98°14'41"W, alt. 2144 m, 26 February 2018, T. Raymundo 7564 ( ENCB), R. Valenzuela 18033 ( ENCB), M. Sánchez 1177 ( ENCB) ; municipality of Naupan , 21°14'38"N 98°09'31"W, alt. 1987 m, 25 September 2017, T. Raymundo 6286 ( ENCB), R. Valenzuela 16921 ( ENCB) ; Veracruz, municipality of Catemaco , Selva El Marinero, 18°25'25"N 94°57'41"W, alt. 1620 m, 24 May 2019, R. Valenzuela 1907 ( ENCB), T. Raymundo 8209 ( ENCB) .

Figures

FIGURE 2. Xylaria sanmartinii (holotype). A. Gregarious and mature stromata on dead wood. B. Young and mature stromata. C, D. Stromata in longitudinal section view. Scale bars: A = 30 mm, B = 25 mm, C = 10 mm, D = 5 mm.

FIGURE 3. Xylaria sanmartinii (holotype).A.Perithecium in longitudinal cut.B.Young perithecium.C. Wall of perithecium.D. Stromatal surface in KOH 5%. E. Stromatal surface in Melzer’ reagent. F. Ascus and ascospores. G. Young ascus. H. Apical ring in 5% KOH. I. Ascospores with conspicuous straight germ slit on the ventral side in 5% KOH. J. Ascospores in 5% KOH. K. Apical ring in Melzer’s reagent. L. Ascospores with conspicuous straight germ slit on the ventral side in Melzer’s reagent. M. Ascospores in Melzer’s reagent. Scale bars:A, B = 200 µm, C = 40 µm, E, D = 100 µm, F = 90 µm, G = 20 µm, H, I = 10 µm, J, K = 40 µm, L, M = 10 µm.

FIGURE 4. Map showing the distribution of Xylaria sanmartinii in the Mexican TMCF.