During explorations of tropical oak forests in central Veracruz (eastern Mexico), the authors discovered a Cantharellus species that produces basidiomes with strikingly violet pileus and a hymenium with yellow, raised gill-like folds. It is harvested locally and valued as a prized edible wild mushroom. Systematic multiyear sampling of basidiomes allowed the recording of the morphological variation exhibited by fresh fruit bodies in different growth stages, which supports the recognition of this Cantharellus species from others in the genus. Two molecular phylogenetic analyses based on a set of sequences of species of all major clades in Cantharellus, one including sequences of the transcription elongation factor 1-alpha (tef-1α) and a combined tef-1α and nLSU region (the large subunit of the ribosome), confirm the isolated position of the new species in a clade close to C. lewisii from USA, in the subgenus Cantharellus. Detailed macroscopic and microscopic descriptions, accompanied by illustrations and a taxonomic discussion are presented.

Cantharellales , ectomycorrhizal fungi, Neotropical fungi, oak forest, wild edible mushrooms

The diversity of species in Cantharellus Adans.: Fr., in combination with their ectomycorrhizal nature (mycobionts of several plant lineages), as well as their highly prized value as edible wild mushrooms, have attracted the attention of specialists from different fields worldwide (Smith and Morse 1947, Trappe 1962, Chandra 1989, Molina et al. 1992, Homola 1993, Thoen 1993, Watling 1997, Danell 1999, Pilz et al. 2002, Lee et al. 2003,Yun and Hall 2004, Boa 2005, Agerer 2006, Arora and Dunham 2008, Kumari et al. 2011, Wilson et al. 2012).

Cantharellus encompasses fungi with long-lived, gymnocarpic, fleshy, variedly coloured, trumpet-shaped basidiomes with nearly smooth, veined, gill-like folded to distinctly lamellate hymenophore, pileipellis poorly differentiated, cystidia lacking, smooth and thin-walled spores, with or without clamps (Wilson et al. 2012, Buyck et al. 2014). In many cases, basidiomes of members of closely related species or inclusive, unrelated look-alike species are difficult to identify in a strict sense, especially if there is not an accurate record of the variation of morpho-anatomical characters and colours in fresh condition. Few microscopic features in the genus had been considered discriminative, especially clamps (presence or absence), wall thickness of the terminal elements of the pileipellis hyphae and the basidiospore features (size and form).

The two former features are considered amongst the most taxonomically informative at subgeneric level and the latter used to distinguish species (Eyssartier and Buyck 2001, Buyck et al. 2014). Additionally, it has been hypothesized that there are cryptic species still undefined taxonomically, even amongst the best known Cantharellus species, especially from tropical regions but also from temperate regions (Smith and Morse 1947, Corner 1966, Heinemann 1958, 1966, Smith 1968, Petersen and Ryvarden 1971, Petersen 1976, Bigelow 1978, Petersen and Mueller 1992, Buyck and Hofstetter 2011, Buyck et al. 2012, Eyssartier et al. 2003, De Kesel et al. 2011, Tian et al. 2012, Wartchow et al. 2012, Buyck and Randrianjohany 2013, Foltz et al. 2013, Buyck et al. 2014, 2016a, c, Leacock et al. 2016).

Taxonomic research on Cantharellus has increased substantially in the last decade, especially by combining DNA and morphological information to support the definition of early recognised species and others recently discovered (Buyck and Hofstetter 2011, Buyck et al. 2011, Tibuhwa et al. 2012, Wilson et al. 2012, Buyck et al. 2012, 2013, 2014, 2015, 2016a, 2016b, Foltz et al. 2013, Shao et al. 2014, Shao et al. 2016, Leacock et al. 2016).

The earliest description of Cantharellus in Mexico dates from Fries (1855), who proposed C. mexicanus based on a specimen with “… pileo carnoso turbinato-infundibuliformi glabro griseofusco… lamellis augustissimis longe decurrentibus”. It was collected by F.M. Liebmann at El Mirador, Veracruz and, years later, considered by Corner (1966) as “… incert. sed. (? Gomphus)…” no longer recorded in the literature. From the same region (Orizaba, relatively near to the current study site), Craterellus confluens Berk. & M.A. Curtis was described by Berkeley (1867). This species is characterised by its yellow basidiomes, it is closely related to Cantharellus lateritius (Berk.) Singer, with which it has been confused or even with other yellow chanterelles, such as C. cibarius Fr. and Craterellus odoratus (Schwein.) Fr. (Heim 1954, Corner 1966, Petersen 1979, Guzmán and Sampieri 1984, Buyck and Hofstetter 2011). After such descriptions of new Cantharellus species from Mexico, only some additional records of about ten species described from other latitudes have been mentioned to occur in different forest ecosystems in the country, including Quercus forests (Guzmán and Sampieri 1984, Guzmán 1985, Guevara et al. 2004, Perez-Moreno et al. 2008, Garibay-Orijel et al. 2009). The identity of these records, however, has not been confirmed with molecular evidence. Recently, C. coccolobae Buyck, Moreau & Courtecuisse was described from the Caribbean (Guadeloupe), including two collections from Yucatán, Mexico (Buyck et al. 2016c).

During the authors’ long term explorations in tropical oak forests in central Veracruz, a Cantharellus species was found with a striking habit, distinctive when compared to the previous records from Mexico. In fact, this fungus is unique because the fresh basidiomes in different growth stages possess a strikingly violet pileus and yellow, raised gill-like folded hymenophore, in combination with ellipsoid basidiopores and terminal elements of pileipellis slightly thick-walled. The macro- and micromorphological features depicted in this fungus, as well as its distinct position in two phylogenetic analyses, one of tef-1α and other of a combined tef-1α+nLSU sequences datasets, allowed its recognition as a new species. This Cantharellus species is locally considered a prized edible mushroom.

Sixty fresh collections were obtained of the violet Cantharellus species, including basidiomes in different growth stages, most of them detected between August-October, in both localities explored. Six new tef-1α and nLSU sequences from three collections were generated in this study (Table 1). In the inferred molecular phylogenies (from tef-1α and tef-1α+nLSU sequences datasets) (Figs 1–2), the generated sequences from the Mexican specimens, clustered in a terminal clade, strongly supported only bootstrap values ≥70 and posterior probabilities ≥0.90 were considered and indicated (BS/BPP) on the branches of each tree. Both trees were congruent and the sequences of the Mexican Cantharellus cluster in a sister clade to C. lewisii from USA, in the subgenus Cantharellus (Buyck et al. 2014). Based on the distinctive morphological features and colour variation of the studied Cantharellus specimens, as well as the isolated position of the samples in the phylogenies obtained, it was concluded that this should be proposed as a new Cantharellus species, which inhabits the tropical Quercus forests in eastern Mexico.

Figure 1. 

Molecular phylogenetic analysis by maximum likelihood of tef-1α sequences dataset of Cantharellus species. Posterior probabilities and Bootstrap values (BPP/BS) are indicated on the tree branches.

Figure 2. 

Molecular phylogenetic analysis by maximum likelihood of tef-1α+nLSU sequences dataset of Cantharellus species. Posterior probabilities and Bootstrap values (BPP/BS) are indicated on the tree branches.

Distinctive features of this species include the medium to large size basidiomes, with pileus practically homogeneously violet pigmented (only fading with age), smooth, with surface free of scales, at times with disrupted pileus surfaces due to age, hymenophore bearing yellow gill-like folds, ellipsoid, medium-sized basidiospores [7–10 (–11) × (4.5–) 5– 6.5 (–7) µm], medium to large basidia [(40–) 45–114 (–125) × (6–) 7–11(–12) µm] and terminal elements of pileipellis 4–6 µm diam, slightly thick-walled (<1 µm thick). Molecular phylogenetic analyses support that the species is genetically distinct from other Cantharellus taxa, in both analyses, C. violaceovinosus was nested in an isolated and well-supported clade (95–99/1) (Figs 1–2).

Cantharellus species with basidiomata having violet pileus are rare but occur in various regions worldwide (Eyssartier et al. 2009; Buyck et al. 2012). Amongst about 45 species of the genus known from USA, Mexico, Central and South America (Guzmán and Sampieri 1984, Guzmán 1985, Eyssartier et al. 2003, Guevara et al. 2004, Henkel et al. 2006, Wartchow et al. 2012, Wilson et al. 2012, Pinheiro and Wartchow 2013, Wartchow et al. 2013, Nascimento et al. 2014, Buyck et al. 2016c), C. lewisii Buyck & V. Hofst., C. atrolilacinus Eyssart., Buyck & Halling and the new C. violaceovinosus are, up to now, the species known to produce basidiomes with violet tints in the Americas.

Cantharellus lewisii grows in floodplain hardwoods, in Water Oak plots next to a Taxodium swamp, in beech-magnolia-loblolly pine forests and also under beech-white oak-loblolly pine-magnolia forests in the south of USA (Buyck and Hofstetter 2011). In the inferred phylogeny, it appears as sister of C. violaceovinosus, but differs because its pileus is pale yellow, dull to greyish-yellow or ochre to pale brownish-orange, sometimes reddish-brown near the margin, with a surface covered with dark purplish-lilac appressed fibrils (in young stages, C. lewisii is often entirely dark lilac-purple) and with terminal elements of pileipellis conspicuously thick-walled (mostly 1–1.5 μm thick) (Buyck and Hofstetter 2011). According to the original description, C. lewisii also differs by its ellipsoid or often somewhat reniform and narrower basidiospores [(7.08–) 7.16–7.62–8.07 (–8.96) × (4.17–) 4.24–4.58–4.93 (–5.21) μm; Q= (1.42–) 1.45–1.57–1.70 (–1.80)] and by 5–6-spored and shorter basidia (60–75 × 7–8 μm) (Buyck and Hofstetter 2011). Two Texan collections of C. lewisii (holotype BB 07.003 and BB 02.197, both at PC) were studied. Based on observations, it was confirmed that this later species differs from the Mexican C. violaceovinosus, because of its markedly reniform, narrower basidiospores, then tending to be “more ellipsoid” [BB 07.003, holotype: 7.5–9.5 × (4–) 4.5–5.5 µm, X–m = 8.4 × 5 µm, Q–= 1.68; BB 02.197: 7.5–10 (–11) × 4–5.5 µm, X–m = 9 × 4.8 µm, Q–= 1.87).

Cantharellus atrolilacinus was described from Costa Rica, growing under Quercus corrugata Hook.) and Q. sp. (Eyssartier et al. 2003). According to the data on this species (R. Halling, www.nybg.org/bsci/res/hall/canlilac.html; Eyssartier et al. 2003), it differs from C. violaceovinosus because its pileus colours tend to be darker, even blackish, dark lilac-grey or brown-lilac, with tomentose surface at the disc, with strong radial, adnate fibrils at the margin, and the stipe whitish with lilac tints. Microscopically, C. atrolilacinus has basidiospores (7–) 7.5–8–8.5 (–9) × 4.5–5–5.5 (–6) μm, tending to be more ellipsoid (Eyssartier et al. 2003, fig. 1:2) and having wider pileipellis hyphae [(4–) 5–10 (–15) μm] with a very thick wall (“..très nettement épaissies..”).

Although Cantharellus amethysteus (Quél.) Sacc. (subg. Cantharellus) from Europe, may appear superficially similar to some forms of C. violaceovinosus, the former however, especially has a pileus surface covered with vinous or lilac, small scales. The authors studied two specimens of C. amethysteus from France (BB 07.284 and BB 07.309 at PC) displaying elongate basidiospores, 9.5–12 (–12.5) × 5–7 µm (X–m = 11–11.2 × 5.9–6.4 µm; Q–= 1.76–1.86), as Eyssartier and Buyck (2000) reported [(9–) 9.5–10.37–11.5 (–12.5) × 6–6.5–7 µm], resulting in being larger and more elongate than in the Mexican species. Also, it is interesting that one sequence of tef-1α of a specimen from Thailand (GB coded KX857062, Table 1) identified as “C. cf. subamethysteus”, appeared close to C. violaceovinosus (Fig. 1). Cantharellus subamethysteus indeed is phylogenetically related to C. lewisii (Buyck et al. 2014) and differs from C. violaceovinosus in the shorter basidiomes (pileus 20–65 mm; stipe 42–57 × 5–11 mm), deep and bright yellow pileus surface, covered with squamules even with rather brown to dark brown tinges, shorter basidiospores [7–8 (8.75) × (4.75) 5–6 μm] and wider pileipellis elements (8–15 μm width) (Eyssartier et al. 2009). Additionally, the hymenophore of this species is rugose to faintly veined (as depicted in the picture accompanying the description).

Cantharellus goossensiae (Beeli) Heinem., C. cyanoxanthus R. Heim ex Heinem., C. subcyanoxanthus Buyck, Randrianjohany & Eyssart. and C. longisporus Heinem. represent African species with basidiomes displaying violaceous tinges (Buyck et al. 2012) therefore, at some stages their basidiomes could resemble those of C. violaceovinosus. However, the three former species have the pileipellis with thin-walled hyphal extremities, thus differing from members of subgenus Cantharellus, including the new species here described. Moreover, the four African taxa have basidiospores distinctly narrowly ellipsoid to elongate (Q>1.70) and often slightly reniform, curved or even somewhat peanut-shaped (Beeli 1928, Heinemann 1958, 1959, Buyck et al. 2012).

Cantarellus violaceovinosus was recorded as a common fleshy mushroom, during the multiyear sampling developed in the tropical Quercus forests studied. It was found in ectomycorrhizal association with native trees of Quercus species. This mushroom was very often recorded in pure stands of Q. oleoides and less frequently in Q. glaucescens and Q. sapotifolia patches. This violet pigmented chanterelle shares the same habit preferences as C. lateritius, also found in the study sites. A similar co-ocurrence has been reported between C. lewisii (the sister relative of C. violaceovinosus) and C. lateritius in the State of Texas in the USA (Buyck et al. 2011). Basidiomes of C. violaceovinosus and C. lateritius are abundant in the local oak forests studied and both are considered choice wild mushrooms although the latter is more highly prized. They are even more appreciated than species of Amanita or Lactarius, representing an income source for wild mushroom collectors. Benefits from mushrooms harvesting, as well as other ecosystemic services, are motivating some owners to conserve relicts of the tropical Quercus forest of the region.

Figure 3. 

Basidiomes of Cantharellus violaceovinosus: a Corona 648 (holotype) b Bandala 4550 c Del Moral 427 d Bandala 4490. Scale bars: 20 mm.

Figure 4. 

Cantharellus violaceovinosus (Corona 648, holotype): a basidiospores b terminal elements of the pileipellis c basidia d pileipellis. Scale bars: 5 µm (a); 10 µm (b, c); 25 µm (d).

Figure 5. 

Cantharellus violaceovinosus: a basidiospores b basidia (Gutiérrez 23) c pileipellis (Herrera 61). Scale bars: 5 µm (a); 10 µm (b); 25 µm (c).

We recognise the support given by CONACYT (CB 252431) to study the EcM fungi associated with tropical species of Quercus in Veracruz, Mexico. M. Herrera is grateful for the scholarship grant from CONACYT (261413). Thanks are given to Dr. B. Buyck (PC) for the loan of herbarium specimens. We appreciate the assistance in the field and in the laboratory to Biol. D. Ramos (Instituto de Ecología, A.C.). Biol. J.C. Corona collaborated in some explorations. We acknowledge the support given by CONACYT (225382) to the Laboratorio de Presecuenciación, Red Biodiversidad y Sistemática, INECOL. Dra. Edith Garay and IBT Bertha Pérez assisted us in some molecular procedures.