Volvariella strangulata (Romagn.) Vizzini & Contu, 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 : 41

10. Volvariella strangulata (Romagn.) Vizzini & Contu, Mycotaxon 112: 28. 2010. ( Fig. 18 )

≡ Volvaria strangulata Romagn. , Bulletin Trimestriel de la Société Mycologique de France 94(4): 371. 1979 [“1978”][basionym] Typification status:— Holotype: Herb. Romagnesi nº 67.48 ( PC)

Description:— Pileus 42–100 mm diam., convex, hemispherical or conico-convex when young, expanding to conico-convex or plano-convex in older specimens, sometimes with a truncate centre; surface smooth; white, sometimes with yellow tinges, not hygrophanous; margin incurved. Lamellae crowded, free, broadly ventricose, white when young, becoming salmon pink or pinkish brown with age. Stipe 64–100 × 8–16 mm, cylindrical, slightly widening towards the base, straight or curved; surface white, with yellow tinges, finely pruinose in upper part. Volva membranaceous, saccate, white, sometimes with yellow or ochre tinges, relatively large, up to 30 mm high, with 3–4 lobes; rhizomorphs not observed. Context white, thin, with fungoid, or intensely sweet, sometimes indistinct, smell.

Basidiospores (n=96, c=2) (6.4–)7.0–8.6(–10.1) × 3.8–5.2 μm, avl × avw = 7.7 × 4.5 μm, Q = (1.40–)1.60–1.90(– 2.0), avQ = 1.70, ellipsoid to oblong, thick-walled, often with a distinct median constriction. Basidia 23.2–48.3 × 9.6–12.9 μm, tetrasterigmate, clavate or subclavate. Lamella edge sterile. Cheilocystidia common, (36–)58–138(–184) × (9–)17–41(–47) μm, broadly fusiform, mostly with an elongated, septate pedicel, with slightly thickened walls. Pleurocystidia common, similar to the cheilocystidia. Pileipellis a cutis or an intermediate cutis-trichoderm, with terminal elements, 12–19 μm wide, and brown intracellular pigment. Stipitipellis a cutis with cylindrical hyphae, 5.8–22 μm wide. Caulocystidia 54–101(–122) × 17–36 μm, present in upper part of the stipe, variable in shape and size, cylindrical, flexuous, clavate, or fusiform. Volva composed of interwoven, cylindrical hyphae, 5.1–19.3 μm wide, with few septa. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Solitary or gregarious. Terrestrial or growing on plant litter. Collected under Fagus sylvatica , Picea abies , and Corylus avellana . July–August.

Distribution:—Recorded from France, Italy, Austria and Spain.

Collections examined:— ITALY. Emilia Romagna: L. Setti, habitat unknown, TOAV141. Lombardia: Bergamo, Valle Seriana, in mixed forest dominated by Corylus avellana and Picea abies , 7 July 2012, A. Ballabeni & L. Setti, ANG07072012; SPAIN. Guadalajara: Cantalojas, hayedo ( Fagus forest) de Tejera Negra, under Fagus sylvatica , 3 August 2013, J.C. Campos, J. Cuesta, J. Herranz, F. Pancorbo, M.A. Ribes, AH44413.

Observations:— Volvariella strangulata is characterized by constricted basidiospores, similar to those of some Hygrocybe species, but not common in the genus Volvariella .

Our description of this species is based on the descriptions of Vizzini and Contu (2010), Campos et al. (2014) and Ballabeni (2017). These descriptions overall agree in the more distinctive morphological characters of this species, like pileus size and colour, and the very particular morphology of the spores. There is some variation in the cystidia sizes as presented by the different authors, which in turn are also different from the very short pleurocystidia (up to 40 μm long) and cheilocystidia (up to 45 μm long) indicated by Moser (2001).

The particular morphology of the spores separates V.strangulata from all other European species with predominantly white basidiomes. Phylogenetically, V. strangulata appears in our analyses ( Fig. 3 ) as sister to V. surrecta , a species also with predominantly white basidiomes, but this species has smaller (avl × avw = 6.3 × 4.1 µm) non-constricted spores, and grows parasitically on other agarics.

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 18. Volvariella strangulata. A–C. Basidiomes. A–B. (ANG07072012); C. (AH44413). D–H. Microscopic characters (ANG07072012). D–E. Cheilocystidia; F. Pleurocystidia; G. Spores; H. Pileipellis. Bar: (D–H) = 10 µm. Photos by L. Setti (A, D–H), A. Ballabeni (B), J.C. Campos (C).