Cortinarius pseudobulliardioides Carteret & Reumaux (2012)

Fellin, Alessandro, Calledda, Federico, Frøslev, Tobias Guldberg, Armada, François, Stohn, Geert Schmidt, Brandrud, Tor Erik, Dima, Bálint, Valdagni, Alessandro & Bellanger, Jean-Michel, 2024, Cortinarius (Basidiomycota, Cortinariaceae) section Crassispori revisited: resolving the C. chevassutii complex and demystifying C. variebulbus, Phytotaxa 663 (5), pp. 247-266 : 258-261

Cortinarius pseudobulliardioides Carteret & Reumaux (2012) , Bull. Soc. mycol. Fr. 128 (3–4): 274 ( Figs. 4 , 5 )

= Cortinarius chevassutii f. personatus Bidaud , in Bidaud et al. (2002), Atlas des Cortinaires 12: 691

Type:— FRANCE. Eure, under Fagus sylvatica and Carpinus betulus , on calcareous soil, 05 November 2012, leg. M. Cerutti, holotype n° 146521 in PC herbarium, isotype XC2013- 176 in X. Carteret pers. herb., GenBank ITS PP919219 and PP919215.

Original diagnosis:— Pileus (30) 50–70 mm, obtuse convexus, late umbonatus , circa umbonem leviter depressus ; margo primum forte involuta, dein lobata , aetate fissa ; indumentum lente hygrophanum, udum brunneo-fuscum (Seg. 701-702) vel fere nigrum, marginem versus fibrillosum, interdum rimosum; velum in umbone adpressum, album vel albo-griseum. Lamellae satis confertae, emarginataesinuatae, paulum ventriosae, brunneae vel brunneo-rufae; acie alba crenulataque. Stipes 50–70 × 15 mm, satis curtus, bulbosus , cum bulbum ovoideum interdum submarginatum (× 20 mm), fibrillosus , pallidus , fere spurcatus , saepe ad apicem glaucescens . Caro grisea , in stipite obscuriora, inodora. Sporae (7,5) 8–9,5 (10) × 5–5,5 (6) μm, ellipsoideae-subamygdaliformes, satis verrucosae. Habitatio in silvis frondosis calcareis.

Updated description:— Pileus 3–12 cm diam., initially globose to campanulate-convex, later plano-convex to depressed, with a broad obtuse umbo, margin lobed or notched, often fissured, involute in young specimens, then inflexed to straight. Surface dry, hygrophanous, showing a pattern of greyish brown, radial fibrils, occasionally with an overlay of radial, micaceous striae, ground colour greyish white when young, later light brown, at maturity tending to blacken in radially arranged areas or striae, with whitish, scattered velar remnants occurring especially towards the center or on the marginal area. Lamellae adnate to emarginate, moderately spaced, argillaceous, later russet. Edge eroded, wavy-toothed, concolorous with the faces or whitish. Stipe (3)4–7(8) × 0.7–1.5 cm, stout, cylindrical, base weakly to distinctly marginate (rarely bulbous, up to 3 cm at base), at times bent downwards, fibrillose, crossed by shiny longitudinal fibrils, concolorous with the pileus, but becoming sordid in old age; velar remnants whitish, more or less restricted to bulb margin, basal mycelium whitish. Context off-white or light brownish with greyish tinges, more pronounced in stipe base. Odour subraphanoid. Macrochemical reactions KOH not tested, guaiac positive, very slow.

Basidiospores [14, 14, 449] 7.1–9.1 × 4.8–5.8 µm, MV = 8.2 × 5.3 μm, intercarpic variation of MV = 7.6–9,1 × 5.1–5.8 µm, Q = 1.40–1.74, Q m = 1.54, intercarpic variation of Q m = 1.45–1.61 ochre-yellow or fulvous in KOH, elliptic or subamygdaliform; apex rounded or tapering; ornamentation variable, consisting of truncate or trapezoidal warts, isolate or forming short ridges, more prominent and tending to coalesce towards the apex; plage present, but hardly differentiated. Reaction to Melzer’s reagent more or less moderately dextrinoid in most collections ( Tab. 3, Figs. 3 , 6 ). Pileipellis suprapellis a cutis of subparallel hyphae, 3–8 µm wide, with cylindrical terminal elements. Pigment yellowish ochre. Subpellis well-differentiated, consisting of much broader hyphae, up to 25 µm wide; localized presence of brownish intracellular pigment associated with yellowish parietal pigment. Basidia 27–40 × 7–9 µm, tetrasporic, cylindro-clavate, hyaline or with greenish brown intracellular pigment. Marginal cells 15–35 × 3–4 µm, lamellar edge sterile, marginal cells in the form of hyaline, cylindro-clavate or sinuous hairs, either unicellular or twoto three-septate, often with lateral diverticula; terminal element cylindro-clavate (15–20 × 5–9 µm). Clamp connections common at all septa.

Habitat and distribution:—With Quercus spp. (including Q. ilex ), Carpinus betulus , Tilia cordata , possibly also Fagus sylvatica and Ostrya carpinifolia on calcareous ground. Mainly in Mediterranean-submediterranean regions, but also in locally thermophilous, temperate sites. So far known only from France, Italy (including Trentino province in N Italy), Germany, and two extreme northern outposts in the Oslofjord area of SE Norway. These Norwegian outposts are from very old, relictual, steep south-facing Tilia cordata-Quercus robur forest remnants.

Material analysed:— FRANCE. Gard, Roquedur, 02 November 2012, Quercus ilex and Quercus pubescens , leg. J.- M. Bellanger, FR 2012257; Hérault, Murviel-lès-Montpellier, 01 November 1999, Quercus ilex , leg. A. Faurite- Gendron, n°5356* in PC herbarium (holotype of C. chevassutii f. personatus ); Isère, Saint-Marcel-Bel-Accueil, 17 October 1998, Quercus pubescens and Carpinus betulus , leg. J. Garin, PML 5357 (paratype of C. chevassutii f. personatus ); Vaucluse, Cadenet, 26 November 2011, forest with Quercus pubescens and Pinus halepensis , leg. J.- M. Bellanger, JMB2011112612;Vaucluse,Saignon, 06 November2021, Quercus ilex ,leg. J.- M.Bellanger, JMB2021110608. GERMANY. Sachsen-Anhalt, Freyburg, FND Kleine Probstei, 01 October 2007, Quercus spp. , Carpinus betulus , leg. M. Huth, HM 01.10.2007; ibid., 03 October 1995, Quercus spp. , leg. M. Huth, HM 03.10.1995; Sachsen-Anhalt, Freyburg, Müncheroda, Langer Berg, 09 October 2010, Quercus spp. , leg. M. Huth, HM 09.10.2010; Sachsen-Anhalt, Freyburg, Balgstädt, NSG Tote Täler, 09 September 2010, Quercus spp. , leg. M. Huth, HM 09.09.2010; Sachsen-Anhalt, NSG Müncheberg, 12 October 2013, Quercus spp. , Carpinus betulus , leg. G. Hensel, HG2013_071; Sachsen-Anhalt, Freyburg, Müncheroda, Schäper Holz, 12 October 2014, Quercus spp. , Carpinus betulus , leg. G. Hensel & M. Huth, HG2014_185; Sachsen-Anhalt, Klosterhäseler, Metzenholz, 20 September 2014, Quercus spp. , Tilia spp. , Carpinus betulus , leg. G. Hensel & U. Täglich, HG2014_184. ITALY. Liguria, Genoa, Chiavari, 10 December 2022, loc. “Le Grazie”, Quercus ilex , leg. F. Calledda & F. Boccardo, n°01995 in TR-gmb herbarium; Liguria, Genoa, Camogli, Parco di Portofino, 18 November 2023, loc. “Portofino Vetta”, forest with Quercus ilex , leg. F. Calledda, n°01999 in TR-gmb herbarium (not studied); Lombardy, Varzi, Pavia, 13 October 2018, loc. “Cella”, forest with Ostrya carpinifolia and Quercus pubescens , leg. F. Calledda, n°01993 in TR-gmb herbarium; Trentino-Alto Adige, Bolzano, Settequerce, 03 November 2013, leg G. Turrini, TG2010-035b; Trentino-Alto Adige, Trentino, Madruzzo, 23 October 2019, loc. “Castel Toblino”, thermophilic forest with Quercus ilex and Ruscus aculeatus , leg. A. Fellin, AF-252-2019; ibid., 21 November 2021, AF-071-2021; ibid., 23 November 2021, AF-077-2021; ibid., 17 November 2022, AF-100- 2022 and AF-101-2022, thermophilic forest with Quercus ilex and Fraxinus ornus ; Trentino-Alto Adige, Trentino, Riva del Garda, 24 October 2022, loc. “monte Brione”, forest with Quercus ilex and Q. pubescens , leg. A. Fellin, AF-110-2022; Veneto, Treviso, Cordignano, 01 November 2007, loc. “Villa di Villa”, forest with Quercus ilex , leg. E. Campo, n° 26645 in MCVE herbarium. NORWAY. Telemark, Bamble, Stokkevann east, 25 October 2014, leg. T. E. Brandrud & B. Dima, TEB 704-14/DB5559; Telemark, Porsgrunn, Blekebakken nature reserve, 29 September 1996, leg. T. E. Brandrud, TEB 29-09-1996.

Comments:—This species has been treated by some mycologists as part of C. chevassutii s. l., and is better known by others as Cortinarius chevassutii f. personatus ( Bidaud et al. 2002) . We show here that this taxon deserves the species rank, based mainly on the well-supported phylogenetic differences, but also on some small differences in spore shape (see above). French mycologists introduced C. chevassutii f. personatus because of some distinctive “key features”, such as the vigorous positive reaction to guaiac on the context (“… Carne ope gaiaco intense cyanea… ”), the size of the basidiomata (“ A typo differ statura majore pileus usque 110 mm side… ”) and the peculiar, strongly fibrillose appearance of the pileus, which is obvious in plate 405 of the Atlas des Cortinaires 12 ( Bidaud et al. 2002). Such morphological features, regarded by the authors as diagnostic, are here judged ineffectual in the separation of the two taxa. All collections of the present species that we studied displayed some phenotypic plasticity for what concerns basidioma size and pileus appearance ( Fig. 5 ), which can also be assessed by comparing the published illustrations of Cortinarius chevassutii f. personatus in the Atlas des Cortinaires 12, pl. 405 ( Bidaud et al. 2002) and of C. pseudobulliardioides in the Bull. Soc. mycol. Fr., 128(3–4), pl. II ( Carteret & Reumaux 2012, reproduced above in Fig. 4 ). As to the reaction to guaiac, a test conducted on fresh material revealed that its discriminating usefulness is rather weak, since the two taxa show a wide variation in positive reactions to the reagent, with often a long response time. In summary, according to our observations, the alleged macro-morphological differences between C. chevassutii and its forma personatus , here treated under the name C. pseudobulliardioides regarding pileus, lamellae and stipe colors or the surface texture of the pileus are not easy to establish objectively, being elements of an intergrading continuum. Therefore, telling the two species apart in the field is very difficult and a reliable identification can be attained only through careful microscopy and in some cases only with sequence data. The two species are known from different countries in Europe, show an almost identical distribution pattern and certainly were confused in the past. Moreover, the two populations cover the same ecological niche represented by thermophilic deciduous forests and are associated with the same host trees ( Chevassut & Henry 1982; Brandrud et al. 1998; Bidaud et al. 2002), coexisting sympatrically in the same environments. Of the three other known members of sect. Crassispori , only C. variebulbus presents risks of confusion with C. pseudobulliardioides (see below), as both C. crassisporus and C. duboisensis are conifer species with different spores and without a marginate-bulbous stipe. The former displays a transcontinental distribution in boreal or hemiboreal conifer forests of Alaska and Fennoscandia ( Niskanen 2014; von Bonsdorff et al. 2015), the latter is a West North American species occurring in woodlands including Pinus ponderosa Douglas ex C. Lawson , Abies grandis (Douglas ex D. Don) Lindl. and Quercus garryana Dougl. ( Li et al. 2016) .

Figures

FIGURE 3. Spore size of Cortinarius chevassutii, C. pseudobulliardioides and C. variebulbus. The lines are drawn on the basis of scatter diagrams and contain 95 % of the spore measurements of each species, as reported in Table 3. X/Y axis: length/width of spores (μm).

FIGURE 4. Cortinarius pseudobulliardioides, holotype, reproduced with authorization from Carteret & Reumaux (2012).

FIGURE 5. Cortinarius pseudobulliardioides, basidiomata. A. coll. TEB704-14/DB5559, Norway (Photo: B. Dima), B. coll. TRgmb01993, Italy (Photo: F. Calledda), C. coll. TR-gmb01995, Italy (Photo: F. Calledda), D. coll. AF-252-2019, Italy (Photo: A. Fellin), E. coll. JMB2010110109, France (Photo: J.-M. Bellanger), F. coll. JMB2011112612, France (Photo: J.-M. Bellanger).

FIGURE 6. Basidiospores of Cortinarius chevassutii, Cortinarius pseudobulliardioides and Cortinarius variebulbus. (Photos G. Boerio). A. Cortinarius chevassutii, coll. TR-gmb01992; B. Cortinarius pseudobulliardioides, coll., TR-gmb01993. C. Cortinarius pseudobulliardioides, coll. TR-gmb01999. D. Cortinarius variebulbus, coll. TR-gmb01250.