Pachyphlodes brunnea Guevara, Pina Paez & Healy, 2021

Paez, Carolina Pina, Healy, Rosanne A., Guevara, Gonzalo, Orijel, Roberto Garibay, Castellano, Michael A., Cazares, Efren & Trappe, James M., 2021, Greetings from belowground: two new species of truffles in the genus Pachyphlodes (Pezizaceae, Pezizales) from Mexico, MycoKeys 82, pp. 159-171 : 159

Pachyphlodes brunnea Guevara, Pina Paez & Healy sp. nov.

Fig. 2a-d

Type.

México, Tamaulipas, Ciudad Victoria, Torre de Microondas "Las Mulas", 23°37'00"N, 99°14'31"W, alt. 1549 m, under Quercus polymorpha Schlecht. & Cham., Quercus sp. and Juglans sp., hypogeous, solitary or in groups of 2, 11 November 2006, col. G. Guevara (holotype: ITCV 896) .

Diagnosis.

Pachyphlodes brunnea is be recognized by the dark brown ascomata and two-layered. Thick (474-570 µm) peridium, white gleba when immature, spores ornamented with capitate columns growing under Quercus and with an odor similar to raw potatoes.

Etymology.

Latin, Pachyphlodes brunnea in reference to the brown peridium.

Description.

Ascomata subglobose to ovoid, 15-17 × 10-15 mm, surface dry, with an irregular basal depression, surface dark brown when fresh (Fig. 2a ), with geometric, angular, or pyramidal warts 1 mm wide, with flattened, elevated, or rounded top. Gleba solid (Fig. 2b ), marbled with white sterile veins separating brownish, fertile tissue, overall brownish when dried. Odor of corn starch-like or of raw potatoes.

Peridium of two layers. Outer peridium 125-570 µm thick, of textura angularis, with warts up to 300-500 (-800) μm high, outermost cells up to 42 μm broad, some ventricose or irregular, radial arrangement in some areas, walls 2-3 (-5) μm thick, reddish-brown to orange-brown in 5% KOH, innermost cells up to 10 μm broad, walls 1-2 μm thick, hyaline in 3% KOH. Inner peridium 120-500 (-700) μm thick, composed of hyaline, septate, interwoven hyphae (textura intricata), 5-12 µm broad, thin-walled 1-2 μm thick. Asci 8-spored, clavate, subclavate, subfusoid or irregular, 120-238 × 30-45 µm including pedicel, hyaline in 5% KOH, walls 1 µm thick, asci are scattered. Paraphyses not detected. Ascospores irregularly biseriate to uniseriate, hyaline in 5% KOH, globose, including ornamentation 18-22 µm broad, mean = 20 µm; excluding ornamentation 12-18 (-20) µm broad, mean = 15 µm. Ornamentation averaging 1.5 (-2.0) µm high, capitate columns, consisting of columns with a boarder, rounded tip.

Distribution and ecology.

Known only from northeastern México (Tamaulipas, Nuevo Leon). Ascomata hypogeous always associated with Quercus polymorpha , and DNA (JN102443) of this species were recovered from sampled roots of oak (JN102443) from Chipinque National Park in Nuevo León. No DNA sequences of this species were found in soil in central or southern México.

Specimens examined.

México, Tamaulipas, Ciudad Victoria, Torre de Microondas "Las Mulas" , 23°37'00"N, 99°14'31"W, alt. 1549 m, under Quercus polymorpha , Quercus sp. and Juglans sp., hypogeous, solitary or in pairs, November 11, 2006, col. G. Guevara (ITCV 891; No ITS); Carretera Victoria, El Madrono, 23°36'3"N, 99°13'8"W, alt. 1460 m, under Quercus canbyi Trel., Q. polymorpha , and Q. laeta Liebm. , hypogeous, August 1, 2008, col. G. Bonito (JT32623; GenBank MT461399 ) . Nuevo León, Municipio de Santiago , El Cercado September 14, 1983, col J. García (UNL 3757; GenBank EU427551 ) .

Taxonomic comments.

The ITS sequences of Pachyphlodes brunnea are similar to those of P. marronina (97.79% of identity and 12 nucleotide differences in ITS region), which is why it was originally described as P. marronina . However, the peridium color and geographic location of these two species differ considerably. Spore ornamentation also separates them. The fresh peridium of P. marronina is red with indistinct warts, while that of P. brunnea is dark brown with distinct angular warts. The angular to pyramidal warts in the peridium of P. brunnea aretaller (300-800 µm) than the lower, indistinct warts on P. marronina (160-270 µm). The spines in P. marronina are taller (1.5-3.0 µm) than P. brunnea (1.5-2.0 µm), conferring a different aspect to the spores overall (Fig. 2e, f ). Pachyphlodes brunnea superficially resembles P. melanoxantha (Tul. & C. Tul. ex Berk.) Doweld and P. annagardnerae R.A. Healy & M.E. Sm., but the latter two are black to the unaided eye, purple under transmitted light, have acute tipped spiny spores, and P. melanoxantha is said to have a nauseous odor ( Berkeley 1844). In contrast, P. brunnea is dark brown to the unaided eye, yellowish-brown under transmitted light, and has a pure white gleba with capitate spore spines and a pleasant odor. Pachyphlodes annagardnerae has no perceptible odor.

Figures

Figure 2. Pachyphlodes brunnea (Holotype: ITCV 896) a ascoma dried b gleba in cross-section c peridium in cross-section, showing a wart composed of isodiametric cells d light microscopy of asci and spores e, f SEM microscopy of spores in surface view. Scale bars: 3 mm (a, b), 20 µm (c, d), 5 µm (e, f).