Volvariella dunensis (Vila, Àngel & Llimona) Justo & M.L. Castro, Mycotaxon

Caballero, Fernando, Justo, Alfredo, Parra, Luis A., Angelini, Claudio, Consiglio, Giovanni, Dovana, Francesco, Ferisin, Giuliano, Kaygusuz, Oğuzhan, Knudsen, Henning, Llimona, Xavier, Muñoz, Guillermo, Daniëls, Pablo P., Pérez-De-Gregorio, Miquel À., Ševčíková, Hana, Valverde, Andrés & Vizzini, Alfredo, 2025, Taxonomic and phylogenetic overview of the genus Volvariella (Volvariellaceae), with a focus on European species, Phytotaxa 680 (1), pp. 1-85 : 27-29

4. Volvariella dunensis (Vila, Àngel & Llimona) Justo & M.L. Castro, Mycotaxon 112: 262. 2010. ( Fig. 12 )

≡ Volvariella nigrovolvacea var. dunensis Vila, Àngel & Llimona, Revista Catalana de Micologia 22: 131. 1999 [basionym]

Typification status:— Holotype: SPAIN. Barcelona , Viladecans (Baix Llobregat), in open dunes, 5 February 1998, J. Vila, F. Àngel, SCM 3512 ! ( BBC).

Description:— Pileus 15–100 mm diam., subglobose or campanulate when young, expanding to convex or plano-convex, without umbo; surface radially fibrillose, sometimes radially fissurate, grey, or bluish grey, with more grey-brown tones in older specimens, dry, not hygrophanous; margin not striate, slightly irregular and exceeding the lamellae. Lamellae crowded to moderately crowded, free, broadly ventricose, white when young, becoming salmon pink or pinkish brown with age, with entire to slightly irregular edge, paler than the faces. Stipe 25–50 × 4–14 mm, up to 20 mm wide at the base, cylindrical to narrowly clavate, straight or slightly curved; surface white, sometimes grey or grey-brown, smooth to finely pubescent. Volva membranaceous, saccate, sometimes quite fragile, off-white, grey, grey-brown, entire, with one longitudinal indentation or with two or more lobes; rhizomorphs absent. Context white, often with grey tones under the pileus to pale beige with indistinct to fungoid smell.

Basidiospores (n=264, c=6) 5.5–9.2 × 3.6–6.8 μm, avl × avw = 7.3 × 5.2 μm, Q = 1.10–1.88, avQ = 1.41, broadly ellipsoid to oblong, rarely subglobose; thick-walled, with barely distinct hilar appendage. Basidia 20–37 × 7–15 μm, tetrasterigmate, (broadly) clavate. Lamella edge sterile or heterogeneous. Cheilocystidia common, 20–89(–120) × 15– 60 μm, clavate, utriform, fusiform or lanceolate, without apical appendages, hyaline, thin-walled, a few with a slightly thickened wall. Pleurocystidia scarce, (34–)40–95(–112) × 13.5–45(–50) μm, clavate, (narrowly) utriform, obovoid, more rarely broadly lageniform or fusiform, hyaline, thin-walled. Pileipellis a cutis or an intermediate cutis-trichoderm, with terminal elements (20–)50–275 (–315) × 10–35(–50) μm, commonly with diffuse, intracellular brown, pigment. Stipitipellis a cutis; hyphae 5–20 μm wide, cylindrical, hyaline, or with diffuse, intracellular brown pigment; with thin, smooth walls. Caulocystidia 20–75 × 10–25 μm, clavate, utriform, lageniform, flexuous, sometimes with elongated or subcapitate apex, without septa, colourless or with diffuse, intracellular brown pigment; with thin, smooth walls; not always present, when present located in the upper part of the stipe. Volva composed of interwoven, cylindrical hyphae, 7–26 μm wide, with common septa; individual hyphal segments often constricted at the septa. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Gregarious, mostly in groups of up to 4 basidiomes. Typically, in open coastal dune habitat, with a good portion of the basidiomes growing deeply buried in the sand. Mostly fruiting November– March in Europe.

Distribution:—Widespread in Mediterranean and Atlantic coastal habitats of southern Europe. Based on molecular data ( Fig. 3 ) also present in India and New Zealand.

Additional collections examined:— SPAIN.A Coruña: Fisterra, among Ammophila arenaria, J.M. Castro Marcote , 27 October 2018, PR12701181361; Balearic Islands: Mallorca, Platja d’Es Trenc, in coastal dunes, 24 November 2003, J. Carbó, JC-20031124-6. Barcelona: Reserva Natural Remolar-Filipinas, Viladecans, in primary dunes close to the sea (15–20 m), under Pinus pinea , among psammophilous plants, 8 February 1997, F. Àngel, SCM3513; ibid., 5 March 2017, F. Caballero & J. Rius, SFC170305; ibid., 12 March 2017, F. Caballero & À. Caballero, SFC 170312; Bizkaia: between Muskiz y Zierbana, in dunes, among Ammophila arenaria , Eryngium maritimum , Tamarix gallica , Carpobrotus edulis , 10 March 2007, R.F. Sasia, RFS07031003; Girona: Sobrestany, Torroella de Montgrí, in dunes 5 km. from the coast with established Pinus pinea , P. pinaster and Quercus ilex , 24 December 2016, M.À. Pérez-de-Gregorio, J. Carbó, N. Macau, C. Roqué & À. Torrent, MPG24122016; ITALY. Sardinia: in dunes among Juniperus phoenicea , J. oxycedrus , Pistacia lentiscus , 26 December 1997, M. Contu, TOAV140; Veneto, Rovigo, Rosolina Mare, on sandy soil near the sea with Quercus ilex , 27 October 2016, G. Ferisin, A. Bizio, FG27112016205; G. Ferisin, A. Bizio, FG27112016205; ibid., on sandy dunes, 16 October 2013, G. Ferisin, A. Bizio, FG1611201323EB; Sant’Anna di Chioggia, close to the sea, in a city park, on sandy soil covered by leaves of Populus alba , 13 January 2023, A. Bizio, L. Lorenzon, A. Parpajola, R. Giolo, P. Di Piazza, FG13012023EB.

Observations:—The above description is based on the collections examined for this study, and the previous descriptions from Justo and Castro (2010) and Vizzini et al. (2011).

Some records of V. volvacea from coastal dune ecosystems in France ( Bon & Gehu 1973; Courtecuisse 1984, 1988) might correspond to V. dunensis , a possibility already pointed out in Vila et al. (1999), Justo and Castro (2010) and Vizzini et al. (2011). All other species recorded by us from dune ecosystems appear in the phylogeny clearly separate from V. dunensis , and morphological characters separate them as well. Volvariella sylvipraticola has a white or very pale grey pileus, and only cystidia rarely. Volvariella taylorii has smaller spores that are often ovoid, larger cystidia with more diverse morphology, often lageniform with elongated apex, a type that is not present in V. dunensis . Volvariella siquieri has smaller predominantly subglobose to ovoid spores, and many basidia that are mono- and bisterigmate, in addition to tetrasterigmate ones.

Figures

FIGURE 3. Best tree from the Maximum Likelihood analysis of the ITS dataset of Volvariella: detailed view of the lineage including V. taylorii and related taxa. BS ≥ 70 % and PP ≥ 0.90 are shown on or below the branches. Newly described taxa are highlighted in red.

FIGURE 12. Volvariella dunensis. A. Habitat. B–F. Basidiomes. B. (PR12701181361); C. (PG24122016); D. (SFC170315); E. (FG27112016205); F. (SFC170312). G–M. Microscopic characters. G–H. Cheilocystidia, G. (MPG24122016), H. (SFC170305); I. Pleurocystidium (SFC170312); J. Spores (J.C.20031124-6); K. Pileipellis (MPG24122016); L.Volva hyphae (SFC170305); M. Stipitipellis (MPG24122016). Bar: (G–M) = 10 µm. Photos by F. Caballero (A, D, G–M), J.M. Castro Marcote (B), M.À. Pérez-de-Gregorio (C), G. Ferisin (E), J. Rius (F).