Caballero, Justo, G. Ferisin, Kaygusuz, Ševčíková, Dovana, Consiglio & L.A. Parra, 2025
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publication ID |
https://doi.org/10.11646/phytotaxa.680.1.1 |
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persistent identifier |
https://treatment.plazi.org/id/A01487E4-FFA9-FF93-FF2E-FF15F7AFFC66 |
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treatment provided by |
Felipe |
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scientific name |
Caballero, Justo, G. Ferisin, Kaygusuz, Ševčíková, Dovana, Consiglio & L.A. Parra |
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sp. |
23. Volvariella neoparvula F. Caballero, Justo, G. Ferisin, Kaygusuz, Ševčíková, Dovana, Consiglio & L.A. Parra , sp.
nov. ( Fig. 31 View FIGURE 31 ).
MycoBank: MB 856540
Typification:— Holotype: ITALY. Gorizia, Farra d’Isonzo, on alluvial soil with Fraxinus excelsior and Quercus sp. , 25 June 2016, G. Ferisin, FG2506201602, GDOR 5558.
Etymology:—From the Latin prefix neo meaning new and parvula (very small), the epithet created by Johannes Anton Weinmann (1782–1858) who described this taxon under the name Agaricus parvulus (now a homotypic synonym of Agaricus pusillus ) whose description (synonyms excluded) matches very well with the new taxon here published.
Diagnosis:— Volvariella neoparvula is macroscopically characterized by a white pileus, often with greyish tones, especially around the centre, silky-fibrillose surface to form small uniformly scattered squamules, a white pubescent stipe and saccate volva.Microscopically it is characterized by the shape of cystidia without apical projection or mucronate tips, spore shape, and clamp connections present only in the rhizomorphs.
Description:— Pileus 25–40 mm diam., convex to conico-convex when young, expanding to plano-convex, with a low central umbo or depressed; surface finely fibrillose or silky-fibrillose, covered with fibrils grouped to form small squamules; pure white usually with faintly greyish or grey-brown tinges, more distinctly so at centre; not hygrophanous; margin striate or not, slightly irregular, exceeding the lamellae. Lamellae moderately crowded, free, narrowly ventricose, white when young, becoming pinkish brown with age, edge regular, concolorous. Stipe 20–60 × 1.5–6 mm (up to 10 mm wide at the base), cylindrical, straight; surface white, finely pubescent. Volva membranaceous, saccate, silky, white or with yellow or grey tones, with 2–4 lobes; in some collections with thin brown rhizomorphs at the base. Context white, thin, with Pelargonium -like smell or indistinct.
Basidiospores (n=316, c=4) (5.0–)5.2–8.1(–10.7) × (3.0–)3.4–5.6 μm, avl × avw = 7.0 × 4.2 μm, Q = 1.22– 2.39, avQ = 1.67, broadly ellipsoid to cylindrical, thick-walled, with distinct hilar appendage. Basidia 16–32 × 7–12 μm, tetrasterigmate, clavate to subcylindrical. Lamella edge sterile. Cheilocystidia common, 36–76 × 12–33 μm, (broadly) fusiform, lageniform with elongated neck, clavate or utriform. Pleurocystidia scarce, 38–72 × 10–36 μm, similar to the cheilocystidia. Pileipellis a cutis with transitions to a trichoderm, with terminal elements 6–25 μm wide, hyaline, often with apical rounded elements detaching easily in microscopic preparations. Stipitipellis a cutis or a cutis-trichoderm in the upper part of the stipe, with cylindrical hyphae 4–15 μm wide, sometimes slightly thick-walled. Rhizomorphs composed of densely packed hyphae, with two different types: septate hyphae 2.6–5.7 μm wide, with clamp connections, thick-walled, with internal pigment olive or brown, and hyphae with perforated walls, up to 7.0–10.0 μm wide, with oleaginous content that exudes outside of the hyphae. Volva composed of interwoven, cylindrical hyphae, 5–39 μm wide, with common septa; individual segments often constricted at the septa; with some differentiated terminal elements, clavate or ovoid. Clamp connections absent in all parts examined, except on the hyphae of the rhizomorphs.
Habit, habitat, and phenology:—Solitary or gregarious. Mostly terrestrial, collected under Corylus , Fraxinus , Pinus , Populus , and Quercus , rarely on decaying deciduous trunks (especially Fagus ). April–October.
Distribution:—Known with certainty from Europe ( Spain, Italy, Estonia, Germany, Czech Republic, Slovakia) and Turkey.
Collections examined. BELGIUM. Vlaams-Brabant: Kampenhout, Natuurreservaat Torfbroek, on soil under hygrophilic hardwoods, 2 October 2019, D. Deschuyteneer, Dov953. CZECH REPUBLIC. Moravia: Chřiby, Čeložnice, near Kolomaznica spring, on soil, under Alnus , 1 September 2007, Jan Běťák JB-CH 158; Dambořice, mixed forest, on soil, 28August 2023, H. Ševčíková, BRNM844467; Lovčice, on soil near small reservoir, 20 September 2018, V.Antonín, H. Ševčíková, BRNM844464; Rozhraní, in soil on organic matter in mixed forest, 30 July 2009, J. Zedník, BRNM 721628; Sidonie, NPR Sidonie, decaying trunk of Fagus , 21 August 2020, S. Flekrová, J. Hrabáková, H. Ševčíková BRNM844462; idem., BRNM844463; Lovčice,alluvium Soudný stream, under Fraxinus and Alnus , on soil, 5 September 2012, Jan Běťák, JB 12/568. ITALY. Belluno: Falcade, directly on soil, among the grass on an artificial embankment, 10 August 2014, G. Ferisin, FG1008201438; Friuli-Venezia Giulia: Forni di Sopra, Rifugio Giaf, under Picea abies , 24 August 2009, G. Consiglio, M. Maletti & L. Setti, GC 09041; ibid., 24 August 2009, G. Consiglio, M. Maletti & L. Setti, GC 09040; Gorizia: Farra d’Isonzo, on river sand near Populus sp. , 13 July 2014, G. Ferisin, FG13072014050; ibid., on alluvial soil, with Fraxinus excelsior and Quercus sp. , 9 August 2014, G. Ferisin, FG09082014013; ibid., on alluvial soil, with Fraxinus excelsior & Quercus sp. , 17 June 2017, G. Ferisin, FG1706201707; Savona: Sassello, at the edge of a path, between patches of mixed broad-leaved trees with a predominance of Ostrya carpinifolia , Acer italicus and Prunus avium , 6 June 2020, F. Dovana, DOV937; Udine, Cervignano del Friuli, in a meadow of Villa Chiozza, 19 October 2014, G. Ferisin, FG1910201456. SPAIN. Gipuzkoa: Aia-Altzola, Erreka, on ground in mixed forest, 9 October 2011, J. Teres , A3033713; Aia-Sagastizabal, on soil among moss, in mixed coniferous and broad-leaved forests, 27 August 2011, P. Arrillaga, A3033714A; Girona: La Ral, Camprodon, in mixed forest, Fagus sylvatica , Quercus robur , Corylus avellana , 27 July 2013, J. Carbó, M.À. Pérez-De-Gregorio & C. Roqué, MPG27072013. La Rioja: Viguera, found on the banks of the Iregua river, among riparian shrub vegetation, elev. 593 m, 13 August 2022, R. Martínez, CMP2386. Zaragoza: Los Fayos, under Populus sp. and Corylus avellana , 7 October 2002, G. Muñoz, GM3631 (AH59937). TURKEY. Denizli: Acıpayam, on sandy soil near Populus tremula , elev. 570 m, 17 October 2011, O. Kaygusuz, OKA-TR1012; ibid., on alluvial soil under P. tremula , elev. 610 m, 11 November 2012, O. Kaygusuz, OKA-TR1013.
Nomenclatural comments:—See under Volvariella pusilla .
Observations:—The species described here as V. neoparvula , corresponds well to the original description (excluding synonyms) of Agaricus parvulus Weinmann , which is a small species with mostly white pileus, but with distinct grey or brown-grey tones at the centre of the pileus. In previous studies, some authors considered V. parvula and V. pusilla as separate species (e.g., Kühner & Romagnesi 1956), while others have considered them synonyms, using V. parvula ( Orton 1986) or V. pusilla ( Boekhout 1990) as the name with nomenclatural priority. However, as V. parvula is a homotypic synonym of V. pusilla , the former name cannot be used for a different taxon.
Volvariella murinella differs from V. neoparvula by having more markedly greyish colours of the pileus; a grey volva; larger basidiospores (7.3 × 4.7 μm on average); and cystidia that are often mucronate or with apical projections. Volvariella pusilla has a white pileus without any greyish tones (sometimes with ochre yellow tinges at centre) and a striate margin, larger basidiospores (7.0 × 4.2 μm on average); and differently shaped cystidia. Volvariella hypopithys differs in having a white pubescent stipe and absence of rhizomorphs. Microscopically it is characterized by the cheilocystidium shape: mostly lageniform with an elongated neck, some with (sub)capitate or tibiiform apex. For a comparison with other species see Tables 1 and 2.
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