Volvariella ranulicystis Kaygusuz, J.L. Siquier, G. Ferisin

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 : 71-74

26. Volvariella ranulicystis Kaygusuz, J.L. Siquier, G. Ferisin , F. Caballero & Justo, sp. nov. ( Fig. 34 ).

MycoBank: MB 856543

Typification:— Holotype: SPAIN. Balearic Islands (Formentera), Torrent de cala Saona, under Pinus halepensis , Juniperus phoenicea and J. oxycedrus , 5 December 2014, J.L. Siquier, AH60253! (Isotype: JLS 3767).

Etymology:—From the Latin “ ranula ” tadpole and the latinized Greek “ cystis ” cystidia, by its often tadpole-shape cystidia.

Diagnosis:— Volvariella ranulicystis is characterized by its small to medium size, the radially fibrillose pileus surface, with grey colours (darker towards centre), and greyish, delicate volva at the stipe base.

Description:— Pileus 10–35 mm diam., convex to conico-convex when young, expanding to applanate or plano-convex, with or without a low, broad umbo; surface fibrillose, with radial fibrils tending to group in minute tufts, especially towards margin, non-hygrophanous, grey to greyish brown at centre, sometimes with an olivaceous tinge, solid white or pale grey towards edge; margin non-striate, smooth, slightly exceeding the lamellae and irregular. Lamellae crowded to rather crowded, free, ventricose to broadly ventricose; white when young, becoming salmon pink or pinkish brown with age; edge entire, or irregular, white or concolorous. Stipe 50–80 × 2–5 mm, cylindrical, slightly widening towards the base (up to 7 mm wide), straight or slightly curved; surface white, smooth or covered with small white fibrils. Volva membranaceous, saccate, white, grey, pale brown or cream, with 2–4 lobes; rhizomorphs not observed. Context white, with Pelargonium -like smell.

Basidiospores (n=174, c=2) (5.0–)5.5–7.4 × (3.2–)3.5–4.8 μm, avl × avw = 6.4 × 4.0 μm, Q = 1.27–1.98, avQ = 1.59, broadly ellipsoid to oblong, thick-walled, with barely distinct hilar appendage, some with median constriction. Basidia 15–30 × 7–10 μm, clavate, subclavate or subcylindrical, tetrasterigmate. Lamella edge heterogeneous. Cheilocystidia common, (35–)40–80(–95) × (10–)15–30(–40) μm, clavate-pedunculate, fusiform to broadly fusiform, lageniform or utriform, hyaline, thin-walled. Pleurocystidia scarce, 45–80 × 10–20 µm, most (narrowly) utriform or lageniform, some fusiform, some with a narrow apical appendage. Pileipellis a cutis or an intermediate cutis-trichoderm, with terminal elements (5–)10–32(–46) μm wide, often constricted at the septa, mostly hyaline contents sometimes in vacuole; with additional globose or subglobose elements, 9.5–21.6 × (5.4–)10.6–16.5(–18.0) µm rising from the side of cylindrical hyphae. Stipitipellis a cutis, or a cutis-trichoderm in the upper part of the stipe, with cylindrical hyphae 5–14 μm wide. Volva composed of interwoven, cylindrical hyphae, 3–16 μm wide, with common septa. Clamp connections absent in all parts examined.

Habit, habitat, and phenology—Gregarious or solitary. Growing in dune ecosystems, under Pinus halepensis , P. pinea , Quercus ilex , and Quercus sp. , with Juniperus phoenicea , J. oxycedrus and Pistacia lentiscus . The Turkish collections were made on forest litter in a broadleaved deciduous forest dominated by Liquidambar orientali s. March– April ( Turkey), October–December ( Spain and Italy).

Distribution:— Spain (Balearic Islands), Italy (Lignano), and Turkey (Burdur Province).

Additional collections examined:— ITALY. Udine: Lignano Sabbiadoro, Camping G-Tour, in grass under Pinus pinea , P. halepensis , Quercus ilex and Quercus sp. , 23 October 2014, G. Ferisin, FG25102014049. SPAIN. Balearic Islands: Formentera, El Ram, in a forest of Pinus halepensis , 6 December 2014, J.C. Salom, JLS 3790. TURKEY. Burdur: Bucak district, close to Karacaören, in Kargı Village Sweetgum Forest Nature Protection Area, on forest litter, Mediterranean forest dominated by Liquidambar orientalis , elev. 260 m, 13 April 2019, O. Kaygusuz, OKA-TR2467; ibid., on soil, under L. orientalis , elev. 265 m, 21 March 2021, O. Kaygusuz, OKA-TR2468 ; ibid., on soil, associated with L. orientalis , elev. 272 m, 12 April 2022, O. Kaygusuz, OKA-TR2469 ; ibid., on soil, associated with L. orientalis , elev. 283 m, 26 March 2023, O. Kaygusuz, OKA-TR2470 .

Observations:— Volvariella ranulicystis is part of a group of species fruiting in Mediterranean dune ecosystems. In this ecosystem, rainfall is concentrated in autumn, with very little precipitation the rest of the year. Other species with similar pileus colours are V. dunensis , V. murinella , V. siquieri and V. sylvipraticola . For a comparison of these taxa see Tables 1 and 2.

Figures

FIGURE 34. Volvariella ranulicystis. A–D. Basidiomes. A. (AH60253, holotype); B. (OKA-TR2469); C–D. (OKA-TR2470). E–J. Microscopic characters (AH60253,holotype).E.Cheilocystidia;F.Pleurocystidia;G. Spores; H.Pileipellis; I.Volva hyphae;J. Stipitipellis. Bar: (E–I) = 10 µm; (J) = 100 µm. Photos by J.L. Siquier (A), O. Kaygusuz (B–D), F. Caballero (E–J).