A new species and a new record of Laccaria (Fungi, Basidiomycota) found in a relict forest of the endangered Fagus grandifolia var. mexicana.

Two species of Laccaria discovered in relicts of Fagus grandifolia var. mexicana forests in eastern Mexico are described based on the macro- and micromorphological features, and their identity supported by molecular analysis of the internal transcribed spacer (ITS) and large subunit (LSU) of the ribosomal RNA gene. The phylogeny obtained here showed that one of the Mexican species is nested in an exclusive clade which in combination with its striking morphological features, infers that it represents a new species, while the other species is placed as a member in the Laccaria trichodermophora clade. This is the first report in Mexico of Laccaria with Fagus grandifolia var. mexicana trees, with which the reported species may form ectomycorrhizal association. Descriptions are accompanied with illustrations of macro- and micromorphological characters and a discussion of related taxa are presented.

Introduction

It has long been recognized that species are important ectomycorrhizal associates of ectotrophic plants worldwide (Mueller 1992). They are known to form interactions, for example with members of the , , , , , PageBreak and (Kropp and Mueller 1999, Wilson et al. 2013). Some species as and have been considered host-generalists, and inclusive, have been subject of a lot of in vitro experimentation worldwide. However, recent studies developed based on molecular systematics showed that under those names, complexes of species are included (Taylor et al. 2006, Jargeat et al. 2010, Vincenot et al. 2012, Sheedy et al. 2013, Popa et al. 2014). A wide ectomycorrhizal host range has also been attributed to , but in this case it has some support for its generalist abilities at the population genetics level by Roy et al. (2008), while consideration for cryptic biological species was discarded, at least among the populations sampled in France.

In the monographic work of by Mueller (1992), 19 species are recognized from North America, and 40 worldwide. New or potential undescribed species from different regions, based on morphological and molecular characteristics of fructifications, or on DNA identifications of environmental samples, have been discovered recently (Wang et al. 2004, Osmundson et al. 2005, Sheedy et al. 2013, Wilson et al. 2013, 2017, Montoya et al. 2015, Luo et al. 2016, Popa et al. 2014, 2016). Nowadays, MycoBank recognizes 112 records in this group of fungi, and additionally, Wilson et al. (2017) inferred 116 phylogenetic species from 30 countries covering the known geographic range of . During the advances on the systematics of the group, a small number of morphological (macro- and microscopic) features had been found taxonomically informative (McNabb 1972, Mueller 1992), which may be the cause of false interpretations, leading to conceptual misunderstandings. In fact, since early taxonomic studies on the group, the need to revise the species of commonly treated under names widely cited in the literature was considered as an important task, due to the existence of different, even undescribed species, confused under apparently well-known ones, such as in the groups of (Scop.) Cooke and (Boud.) Pat. (Singer 1967, Mueller and Sundberg 1981, Irving et al. 1985). For example, the study by Sheedy et al. (2013) based on DNA multigene sequences, even noted that cryptic phylogenetic species were not nested as sister taxa. Thus, strict species identifications and achieving phylogenetic inferences with stronger resolution in , will aid in building a robust data set, dealing with each species ectomycorrhizal host range.

In Mexico, the reports of the diversity of the genus include about 17 species (Aguirre-Acosta and Pérez-Silva 1978, Bandala et al. 1988, Montoya et al. 1987, 2015, Cifuentes et al. 1990, Pérez-Silva et al. 2006, Garibay-Orijel et al. 2009). The edibility and use of some species as food has been documented (e.g. Montoya et al. 1987, Montoya-Esquivel et al. 2002, 2003, Lampman 2007, Pérez-Moreno et al. 2008) and ectomycorrhizae formed under in vitro culture conditions, isolated from native specimens have also been achieved (Santiago-Martínez et al. 2003, Carrasco-Hernández et al. 2010, Galindo-Flores et al. 2015). Molecular studies on most of those records are needed not only to support their identifications but for being included in phylogenetic studies. T. J. Baroni, Montoya and Bandala, described as new (Montoya et al. 2015) from the mesophytic forest in Veracruz, was recognized under morphological features and confirmed through phylogenetic DNA sequence analyses and recently incorporated by Luo et al. (2016) in their moPageBreaklecular phylogeny to confirm the distinction of the new X. Luo, L. Ye, Mortimer & K.D. Hyde from China.

We have under research the fungal community associated to the two southernmost relicts of mesophytic forests dominated by in the American Continent. This tree species is currently in danger of extinction and in the Red list of Mexican cloud forest trees, inhabiting a narrow range of nearly 145 hm2 in Mexico (Rodríguez-Ramírez et al. 2013, Montoya et al. 2017). Taking into account its current status, we consider important to document the associated fungal species with particular focus to the ectomycorrhizal forming species. During our study, we found two species of which after their morpho- and molecular analyses we concluded that with strong support can be recognized, one as G.M. Mueller and the other, as a distinct undescribed species close to Zhu, L., Yang & L. Wang from China. As both are part of the unknown potential mycobionts of this endangered ectotrophic tree species, we were motivated to document them.

Materials and methods

Sampling and morphological study of basidiomes

Random visits were conducted during August–September 2005 and 2007, in two stands of from Veracruz, Mexico, one in Acatlán Volcano, Acatlán (, 1840 m) and the other in Mesa de la Yerba, Acajete (, 1900 m). Basidiomes of growing close to were gathered. Macromorphological characters and color were recorded, alphanumeric color codes in descriptions refer to Kornerup and Wanscher (1967). Measurements and colors of micromorphological structures were recorded in 3% KOH. Basidiospores were studied in Melzer’s reagent. Methods to determine spore ranges are those used by Montoya and Bandala (2003), with 45–50 spores measured per collection (length and width of the sporoid excluding the ornamentation) and given as a range with the symbol X̅ representing mean values. Q̅ represents the basidiospore length/width ratio and is given as range of mean values. Line drawings were made with a drawing tube. The examined specimens studied are deposited in XAL herbarium (acronym from B. Thiers, continuously updated; Index Herbariorum: http://sweetgum.nybg.org/ih/). The SEM images were obtained after critical point drying of pieces of lamellae previously rehydrated in ammonia, fixed in glutaraldehyde and dehydrated in an ethanol series (Bandala and Montoya 2000).

DNA extraction, PCR amplification, and sequencing

Genomic DNA of the Mexican specimen was extracted according to Montoya et al. (2014). PCR was performed to amplify the ITS (Internal Transcribed Spacer) and LSU (Large Subunit) regions of the nuclear rDNA, using primers ITS1F, ITS5/ITS4, PageBreakLR0R/LR21, LR7 (Vilgalys and Hester 1990, White et al. 1990, Gardes and Bruns 1993). PCR conditions, as well as procedures for the purification of amplified PCR products, cycle sequencing reactions and their purification were done according to Montoya et al. (2014). Once sequences were assembled and edited, they were deposited at GenBank database (Benson et al. 2017) (Table 1).

Table 1.

taxa included in this study: samples, location and GenBank accession number for sequences.

Taxon	Voucher	Location	GenBank
			ITS	28S
Cortinarius violaceus	MTS 4854 (WTU)	USA: Washington	DQ486695	DQ457662
L. alba	AWW438	China: Yunnan-Shangrila	JX504094	JX504178
L. alba	F1120750	China	JX504126	JX504206
L. alba	F1121461	China	JX504129	JX504209
L. alba	GMM6131	China: Chang Bai Shan	JX504131	JX504210
L. amethystea	FP-98556	Germany: Vorpommern	DQ499640	–
L. amethystea	TUB 011464	Germany	AF539737	–
L. amethysteo-occidentalis	AWW556	USA: California, Nevada Co.	JX504107	JX504191
L. amethysteo-occidentalis	AWW590	USA: Oregon, Benton Co.	JX504112	JX504195
L. amethystina	ALB183	China: Tibet	JX504092	JX504176
L. amethystina	F1123822	USA: Wisconsin	KU685760	KU685911
L. amethystina	GMM7041	Russia: Caucasus	KU685654	KU685797
L. amethystina	GMM7621	France: Forest comaniale de Ste. Croix	JX504150	JX504224
L. amethystina	LaAM-08-1	–	JGI Genome	JGI Genome
L. angustilamella	BAP226	China: Yunnan	JX504118	JX504201
L. angustilamella	HKAS58714	China: Yunnan, Yongping	JX504168	JX504244
L. aurantia	KUN-F 78557-Type	China: Yunnan	JQ670895	–
L. aurantia	MB-FB-101109	China: Yunnan	JQ681209	–
L. bicolor	AWW539	USA: Illinois	KM067817	KU685763
L. bicolor	AWW537	USA: Illinois, Johnson Co.	JX504105	JX504189
L. major	GMM6012	Costa Rica	KU685758	KU685909
L. major	GMM6019	Costa Rica	KU685757	KU685908
L. nobilis	F1091206	USA: Michigan	KU685636	KU685779
L. ochropurpurea	JMP0038	USA: Wisconsin	EU819479	–
L. ochropurpurea	KH_LA06_016	USA: Louisiana	KU685721	–
L. ochropurpurea	PRL3777	USA: Illinois	KU685732	JX504246
L. ochropurpurea	PRL4777	USA: Illinois	KU685733	KU685883
L. proxima	F1133825	USA: Mississippi	KU685642	KU685786
L. roseoalbescens	LM5042	Mexico: Veracruz	KJ874327	KJ874330
L. roseoalbescens	LM5099-Type	Mexico: Veracruz	KJ874328	KJ874331
L. salmonicolor	GMM7596-Type	China: Tibet	JX504143	JX504218
L. salmonicolor	GMM7602	China: Tibet	JX504145	JX504220
L. sp.	A0561	Japan: Sapporo	JX504082	–
L. sp.	A0573	Japan: Narusawa	KU685617	–
L. sp.	GMM6800	Guatemala	KU685756	KU685907
L. squarrosa a	DM121	Mexico: Veracruz	MF669960	MF669967
L. squarrosa a	DM63-Type	Mexico: Veracruz	MF669958	MF669965
L. squarrosa a	DM93	Mexico: Veracruz	MF669959	MF669966
L. trichodermophora	TENN42523-Type	USA: Texas	DQ149868	–
L. trichodermophora	F1111951	Costa Rica	KU685640	KU685784
L. trichodermophora	GMM7733	USA: Texas, Tyler Co.	JX504157	JX504230
L. trichodermophora	KH_LA06_013	USA: Louisiana	KM067881	KU685872
L. trichodermophora	GMM7735	USA: Texas	KM067872	–
L. trichodermophora	KH-LA06-012	USA: Louisiana	KM067880	–
L. trichodermophora	GMM7734	USA: Texas	KM067871	–
L. trichodermophora	KH-LA06-007	USA: Louisiana	KM067874	–
L. trichodermophora	KH-LA06-008	USA: Louisiana	KM067875	–
L. trichodermophora	tri1125225	USA: Rocky Mountains	DQ149855	–
L. trichodermophora	KH-LA06-010	USA: Louisiana	KM067878	–
L. trichodermophora	KH-LA06-011	USA: Louisiana	KM067879	–
L. trichodermophora	KH-LA06-009	USA: Louisiana	KM067876	–
L. trichodermophora	KH-LA06-009B	USA: Louisiana	KM067877	–
L. trichodermophora	KH-LA06-004	USA: Louisiana	KM067873	–
L. trichodermophora	HC-PNNT-112	Mexico: Mexico State	KT875031	–
L. trichodermophora	GO-2009-266	Mexico: Mexico State	KC152147	–
L. trichodermophora	HC-PNNT-157	Mexico: Mexico State	KT875032	–
L. trichodermophora	GO-2009-305	Mexico: Distrito Federal	KC152149	–
L. trichodermophora	GO-2010-124	Mexico: Veracruz	KC152144	–
L. trichodermophora	EF36	Mexico	KT354980	–
L. trichodermophora	CB08167	Mexico: Mexico State	KT875029	–
L. trichodermophora	GO-2009-228	Mexico: Mexico State	KC152146	–
L. trichodermophora	GO-2010-126	Mexico: Veracruz	KC152145	–
L. trichodermophora	GO-2010-082	Mexico: Tlaxcala	KC152152	–
L. trichodermophora	GO-2009-225	Mexico: Mexico State	KC152143	–
L. trichodermophora	GO-2009-484	Mexico: Tlaxcala	KC152151	–
L. trichodermophora	HC-PNNT-192	Mexico: Mexico State	KT875033	–
L. trichodermophora	GO-2009-210	Mexico: Mexico State	KC152148	–
L. trichodermophora	HC-PNNT-132	Mexico: Mexico State	KT875030	–
L. trichodermophora	GO-2009-314	Mexico: Jalisco	KC152150	–
L. trichodermophora	HC-PNNT-099	Mexico: Mexico State	KT875034	–
L. trichodermophora	GMM7714	USA: Texas	KM067867	–
L. trichodermophora	GMM7712	USA: Texas	KM067866	–
L. trichodermophora	GMM7716	USA: Texas	KM067869	–
L. trichodermophora	HMJAU26938	–	KP128033	–
L. trichodermophora	GMM7703	USA: Texas	KM067865	–
L. trichodermophora	GMM7697	USA: Texas	KM067863	–
L. trichodermophora	GMM7698	USA: Texas	KM067864	–
L. trichodermophoraa	Montoya 4393	Mexico: Veracruz	MF669961	MF669968
L. trichodermophoraa	Montoya 4394	Mexico: Veracruz	MF669962	MF669969
L. trichodermophoraa	AR24	Mexico: Veracruz	MF669964	MF669970
L. trichodermophoraa	Bandala 4282	Mexico: Veracruz	MF669963	–
Psathyrella rhodospora	MP133 MN	–	DQ267129	AY645058

asamples and sequences obtained here.

Phylogenetic methods

The phylogenetic analysis was performed with the sequences obtained in this study, as well as some retrieved from GenBank (http://www.ncbi.nlm.nih.gov/) derived from the Blast analysis (only those that best match), and complemented with related sequences used by Osmundson et al. (2005), Montoya et al. (2015) and Wilson et al. (2017) (Table 1). For this purpose, we constructed a dataset (ITS+LSU) using PhyDE v.0.9971 (Müller et al. 2010), also with MEGA 6.06 (Tamura et al. 2013) calculated the best evolutionary model and constructed the phylogenetic tree under the method of Maximum Likelihood (ML) with 500 bootstrap replications, and finally with MrBayes v 3.2.6 (Ronquist et al. 2012) constructed the phylogenetic tree (as Montoya et al. 2014) under the method of Bayesian Inference (BI). The phylogenies from ML and BI analyses were displayed using Mega 6.06 and FigTree v1.4.3 (Rambaut 2016) respectively.

Results

A total of 13 new ITS and 28S sequences for were generated in this study (Table 1 and alignment in TreeBASE S21413). They were obtained from samples proceeding from the two stands of in the subtropical cloud forest in central Veracruz (sample AR24 comes from a conifers forest in Veracruz) (Table 1). Only bootstrap values of ≥70% and posterior probabilities (ML/PP) of ≥0.90 were considered and indicated on the tree branches. The phylogeny displayed (Fig. 1) inferred the Mexican samples clustered in two distinct clades. A group clearly related to and another, in a separate clade, representing an undescribed species.

Figure 1.

Phylogenetic relationships within species inferred from the combined ITS and LSU sequence data by maximum likelihood method. Tree with the highest log likelihood (–4163.7219), the percentage of trees in which the associated taxa clustered together (only values ≥ 70% are considered) is shown next to the branches, followed by the posterior probabilities (only values ≥ 0.90 are indicated) obtained after Bayesian inference. The tree is drawn to scale, with branch lengths measured in the number of substitutions per site.

Taxonomy

Bandala, Montoya & Ramos sp. nov.

823034

Figs 2 , 3 , 4 , 5

Figure 2.

, basidiomes. a, b habit c, d pileus surface details a, c DM 121 b DM 63 (holotype) d DM 93. Scale bars: 10 mm.

Figure 3.

, lamellae attachment and habit. a, c DM 121 b DM 63 (holotype) d DM 93. Scale bars: 10 mm.

Figure 4.

, a basidiospores b pleurocystidia c cheilocystidia d basidia a, c DM 121 b DM 63 (holotype) d DM 93. Scale bars: 5 µm (a); 10 µm (b–d).

Figure 5.

, a–b basidiospores under SEM c–f details of the pileipellis c–d cutis (arrow indicating scales) e–f details of the pileipellis scales c–f DM 63 (holotype). Scale bars: 5 µm (a); 2 µm (b); 100 µm (c); 20 µm (d); 50 µm (e–f).

Holotype.

MEXICO, Veracruz State, Mpio. Acatlán, Volcán de Acatlán, Aug 14 2007, DM 63 (XAL). Terrestrial under .

Diagnosis.

Differs from other species by having medium sized basidiomes, with pinkish to pale brownish-orange colors, smooth to finely squarrose surfaces, especially on the stipe, basal mycelium with whitish to pale brownish with pinkish tinges, and globose, echinulate basidiospores, 7–10 (-11.5) × 7–10.5 µm, with the echinulae 0.5–1.4 in length, 0.45–0.9 µm in width at base, subcylindrical to contorted cystidia and pileipellis arranged in a cutis with mounds of intermixed and irregularly projected hyphae.

Gene sequences ex-holotype.

MF669958 (ITS), MF669965 (LSU).

Etymology.

referring to the characteristic squarrose surfaces of basidiomata.

Pileus 10–82 mm diam convex to plane-convex, at times slightly depressed at center, surface squamulose to squarrose with age, pinkish (6B3–2) with pale yellowish tinges PageBreaktowards the center or brownish-orange (5B6–5) when young; margin recurved, striate, edge thin. Lamellae 1–8 mm in length, adnate to subdecurrent, at times slightly undulate, subdistant or distant, pinkish to pale pinkish (6B4), 1–2 lamellulae per lamellae of different sizes. Stipe 50–155 × 5–9 mm, cylindrical, widened towards the base, squamulose to squarrose overall, more densely scaly towards the apex and when old, squamules brown, pinkish to ochraceous or ochraceous-orange. Basal mycelium pale whitish to brownish (6D6), with pinkish tinges in some areas. KOH negative overall surfaces.

Basidiospores 7–10 (-11.5) × 7–10.5 µm, X̅=7.8–10.7 × 7.7–9.48 µm, Q̅=1.01–1.12, globose, pale brownish, thin walled, hyaline, inamyloid, echinulate; under SEM the echinulae appear acute, 0.5–1.4 in length, 0.45–0.9 µm in width at base, shorter towards the hylar appendix area, this latter structure (also called the apiculus) consisting of a tube with rounded ending. Basidia 35–66 × 10–15 µm, clavate to narrowly clavate, thin walled, mostly tetrasporic, at times tri- or bisporic, sterigmata 10 µm length, some with refringent contents, clamped, hyaline. Pleurocystidia 20–38 × 3–6 µm, subcylindrical, contorted, sinuous, hyaline, thin walled. Cheilocystidia 14–40 × 2–5 µm, subcylindrical, rarely narrowly utriform, contorted, sinuous, hyaline, thin walled. Pileipellis a regular compact cutis, hyphae periclinally oriented, also with projected mounds of intermixed hyphae, which form the pileus scales irregularly projected; hyphae cylindrical, some widened 4–10 µm diam, some septate, hyaline, inamyloid, yellowish in PageBreakmass and somewhat refringent in some parts, thin walled, clamped. Context hyphae cylindrical, faintly yellowish in mass, 4–9 (-14) µm diam, thin walled, up to 1 µm diam, hyaline, inamiloyd, septate. Hymenophoral trama regular, compact, composed by cylindrical hyphae, pale yellowish in mass, 3–8 µm diam, septate, hyaline and inamyloid, thin walled. Clamps present.

Habitat.

Terrestrial, solitary, under .

Additional studied material.

MEXICO, Veracruz, Mpio. Acatlán, Volcán de Acatlán, Sep 18 2007, DM 121. Mpio. Acajete, Mesa de la Yerba, Aug 28 2007, DM 93 (all at XAL).

Discussion

In the phylogeny presented here that is based on sequences used in the worldwide survey of by Wilson et al. (2017) and complemented with some from GenBank (Fig. 1) and sequences of , described here, this new taxon is clearly shown to be phylogenetically isolated from other species. is disPageBreaktinct by possessing typical medium sized basidiomes with scaly surfaces, more obvious especially on the stipe and by having the basal stipe mycelium whitish to pale brownish with pinkish tinges. Microscopically it differs by globose, echinulate basidiospores, cylindrical cystidia and pileipellis arranged in a cutis with mounds of intermixed and irregularly projected hyphae. In Fig. 1, is shown to be phylogenetically close to Zhu L., Yang & L. Wang from China. This later species is characterized, however, by having a marasmioid to mycenoid habit, with a short basidiome size (pileus 20–30 mm diam), narrow (2 mm length) and subdistant lamellae, PageBreaknon-scaly stipe, with more ellipsoid basidiospores (Q up to 1.18) and larger echinulae (2.0–) 2.5–5.0 µm long and up to 2.5 µm wide at base (Wang et al. 2004).

Color features of the basidiomes and whitish mycelia relate to metasection (Mueller 1992), where it superficially resembles (Boudier) Patouillard. This later species, however, can be distinguished based on the longitudinally striate stipe, with a fibrillose surface only, ellipsoid basidiospores [9–11.5 × 6.7–8 (-8.8) µm, Q = 1.25–1.35 (-1.4)], having shorter echinulae (0.5–1 µm length), pleurocystidia absence and larger cheilocystidia [19–66.5(-92) × 2–8.5(-16.5) µm] (Mueller 1992). Among the species in the genus, A.H. Smith, G.M. Muell., and (Berk.) Peck also produce fibrillose to somewhat scaly pileus surfaces. even can have recurved scales on the stipe surface. However, all those taxa clearly differ from by basidiomes and mycelia with violaceous colors, besides other macro and microscopical features (Mueller 1992).

G.M. Mueller (Figs 6–7) was previously reported from Mexico (as sensu Singer) by Montoya et al. (1987) from conifer forests of Cofre de Perote National Park areas. The collections from forest here studied, were collected in the locality of Mesa de la Yerba (Veracruz), on Aug 04 2005, Montoya 4393, Montoya 4394; Aug 28 2007, Bandala 4282 (XAL). Excepting by narrower hyphae disposed in the pileipellis mounds and the basidiospores including broadly ellipsoid to ellipsoid shapes, exhibit a similar morphological variation as those described by Mueller (1984, 1992) and other collections reported before from Mexico. A summary of the main morphological features that characterize the studied materials are: pileus 15–55 mm diam, fibrillose to fibrillose-minutely scaly, brownish-orange (6C6–C7), light brown or pale pinkish-brown or pale brownish towards the margin (6D6, 7C5–C4), hygrophanous. Lamellae 2‒6 mm in length, adnate to sinuate, close to subdistant, pinkish or incarnate (6A2‒B3). Stipe 20–75 × 2–8 mm, cylindrical, attenuated towards the apex, striate, fibrillose and fistulous. hygrophanous, concolorous to pileus but more pinkish-violaceous (13CD2) towards the base. Basal mycelium violaceous becoming white. Basidiospores 6–9 (-10) × 6–8.5 (-10) µm, X̅= 6.9–8.18 × 6.84–7.9 µm, Q̅= 1.00–1.05, globose, hyaline, echinulate, under SEM the echinulae appear 0.8–1.13 × 0.6–0.8 µm. Basidia 27–65 (-80) × 7–13 µm, clavate, tetra or at times tri-sporic, hyaline, thin walled, clamped. Cheilocystidia 12–49 × 2–6 µm cylindrical to narrowly clavate, at times somewhat utriform, hyaline, thin walled, frequently clamped. Pileipellis composed of periclinally oriented hypahe 3–10 µm diam, in a more or less cutis arrangement but with frequent mounds of intermixed or erect hyphae, with terminal elements 25–125 × 10–13 µm, cylindrical to clavate other somewhat utriform 20–65 × 5–17 µm. Clamps present.

Figure 6.

, a basidiospores b pleurocystidia c basidia d pileipellis e cheilocystidia a–e Montoya 4393. Scale bars: 5 µm (a); 10 µm (b–c, e); 25 µm (d).

Figure 7.

, a–b basidiospores under SEM c–d pileipellis a, c–d Montoya 4393 b Bandala 4282. Scale bars: 1 µm (a–b); 50 µm (c); 25 µm (d).

In the phylogeny obtained (Fig. 1), the sampled sequences of this species appear in three clades. One of them, with collections from North America, included the type specimen (DQ149868) and 21 specimens from Mexico. Our collections clustered in this later lineage interestingly with one sample from Costa Rica too. The other two clades are composed of specimens from Texas, one of them sister to the type clade, and PageBreakthe third clearly separated, probably representing an undescribed species. A specimen (KP128033) labeled as in the GenBank, clustered in group from Asia in our analysis. This sample lacks geographic information and could well be a misidentified collection.

There are no previous reports of being associated with . This report serves as the first documentation of this association. According to the reports of , it shows a wide ecological range. Mueller (1992) observed that all collections of this species from the southeastern United States appeared to be associated with . He also collected it, in Costa Rica, beneath Neotropical species of . In central Mexico, in the states of Tlaxcala and Michoacán, it has been recorded associated to mixed - and - forests (Montoya et al. 1987, Montoya-Esquivel et al. 2004). In the eastern part of Mexico, in Veracruz, it has been found (as sensu Singer) in monodominant and mixed - forests (Montoya et al. 1987). In this later country, it is interesting to note that, basidiomes of this species, specially from conifers, are sold in local markets as edible fungi (Montoya et al. 1987, Montoya-Esquivel et al. 2004). Based on the available ecological information of the samples in the phylogenetic tree (Fig. 1), a wide host range for type specimen clade can be inferred. Among the potential hosts, it can be recognized as occurring with , , and sp. in Texas, as well as , other species of and spp. in both US and in Mexico, and the endangered as confirmed here. represents another host also, PageBreakas proved by data from two sequences (MF669964 and MF669970) (Table 1, Fig. 1) obtained here, from the sample AR24, from an forest at Cofre de Perote National Park in Veracruz, Mexico.