Volvariella bombycina (Schaeff.) Singer var. bombycina, Lilloa

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 : 18-20

1. Volvariella bombycina (Schaeff.) Singer var. bombycina, Lilloa 22: 401. 1951 [“1949”]. ( Fig. 8 )

≡ Agaricus bombycinus Schaeff., Fungorum qui in Bavaria et Palatinatu circa Ratisbonam nascuntur Icones 4: 42. 1774, nom. sanct. (Fr., Syst. Mycol. 1: 277. 1821) [basionym]

≡ Pluteus bombycinus (Schaeff.) Fr., Anteckningar Öfver de i Sverige Växande Ätliga Svampar: 34. 1836

≡ Volvaria bombycina (Schaeff.) P. Kumm., Der Führer in die Pilzkunde: 99. 1871

≡ Volvariopsis bombycina (Schaeff.) Murrill, Mycologia 3(6): 281. 1911

Typification status:— Lectotype, designated here: [icon] “ Agaricus octogesimus septimus ” in J. C. Schaeffer, Fungorum qui in Bavaria et Palatinatu circa Ratisbonam Nascuntur Icones 1: Tab. XCVIII, Fig. V. 1762. MycoBank type: MBT 10023144.

Description:— Pileus 40–180(–200) mm diam., ovoid when young, expanding to convex or plano-convex, usually with a distinct umbo; surface silky-fibrillose, typically with fibrils grouped to form small squamules that are uniformly scattered; white, discolouring pale yellow to almost light ivory when bruised or with age, dry, not hygrophanous; margin not striate, straight, inflexed or exceeding the lamellae. Lamellae crowded, free, broadly ventricose, white when young, becoming salmon pink or pinkish brown with age, with entire to slightly irregular edge, paler than the sides. Stipe 70–180 × 10–20 mm, cylindrical to subclavate, often curved; surface white, sometimes with yellow tinges, smooth or slightly fibrillose. Volva membranaceous, off-white, brown-grey or brown, or with scattered brown spots on outer surface; with 2–4 lobes. Context white with indistinct smell.

Basidiospores (n=289, c=6) (6.5–)6.9–10.2 × 5.1–7.6 μm, avl × avw = 8.5 × 5.9 μm, Q = 1.15–1.67, avQ = 1.44, broadly ellipsoid to oblong, thick-walled, with barely distinct hilar appendage. Basidia 28–49 × 9–13.5 μm, tetrasterigmate, clavate to subcylindrical. Subhymenium composed of cells with irregular outline, reminiscent of jigsaw puzzle pieces, with prominent nodules, 35–77 × 10–31 μm, with hyaline, or pale grey cytoplasmatic content. Lamella edge sterile. Cheilocystidia common, 35–158(–170) × 12–41(–60) μm, fusiform, narrowly clavate, lageniform, usually with elongated apex, rarely utriform, hyaline, thin-walled. Pleurocystidia scarce, 62–111 × 13–35 μm, (narrowly) fusiform, narrowly clavate, lageniform, narrowly utriform, hyaline, thin-walled. Pileipellis a cutis or an intermediate cutis-trichoderm, with hyphae 3–29 μm wide in the upper layer, and 15–48 μm wide in the lower layer, mostly hyaline, or rarely with diffuse, intracellular, pale yellow pigment. Stipitipellis a cutis, or a cutis-trichoderm in the upper part of the stipe, with cylindrical hyphae 3–23 μm wide. Volva composed of interwoven, cylindrical hyphae, 8–22 μm wide, with few septa, often gelatinized on the external surface. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Solitary or gregarious. Growing on angiosperm wood, on living trees and dead stumps, mostly Populus and Ulmus but also Aesculus, Celtis , Fagus , Fraxinus , and Quercus ; also reported by Shaffer (1957) in North America on Acer, Magnolia , and Mangifera . Common in urban settings on a wide variety of hosts, e.g., Acer negundo , Celtis australis , Morus alba , Populus alba var. bolleana , Styphnolobium japonicum , and Ulmus pumila just in the city of Madrid ( Spain) ( Daniëls & Borrajo 2021). Rarely on piles of straw. One collection (BRNM844468) was found at the base of a coniferous tree ( Picea ). Mostly fruiting April–November.

Distribution:—Widespread in the temperate and tropical areas of the Northern Hemisphere. Also recorded, and molecularly confirmed, from the Southern Hemisphere ( Menolli & Capelari 2008).

Collections examined:— CZECH REPUBLIC. Bohemia: Praha, Klánovice, Klánovický les, Piceetum with Pinus , at base of Picea , 5 July 2018, J. Schneider, BRNM844468. FRANCE. Pyrénées-Atlantiques: Lizarrusti, on dead log of Fagus sylvatica , 25 June 2005, J.M. Lekuona, ARAN-FungiA3043167. ITALY. Trieste: Basovizza, on Aesculus hippocastanum , 31 August 2018, G. Ferisin, FG31082018-01. Udine: Cervignano del Fruili, on Aesculus hippocastanum , 9 May 2020, G. Ferisin, FG09052020-344. Emilia-Romagna: Bologna, Parco Cavaioni, in a forest of Quercus pubescens , 20 August 1995, G. Consiglio, AMB19312. SPAIN. Barcelona: Barcelona city, on live Populus nigra , 12 October 2013, F. Caballero, SFC 131012; St. Fost de Campsentelles, on living Populus nigra , in a garden area, 24 September 2020, F. Caballero, SFC 200924; ibid., 26 September 2020, F. Caballero, SFC 200926; ibid., 29 September 2020, F. Caballero, SFC 200929; ibid., 15 October 2020, F. Caballero, SFC 201015; ibid., 16 October 2020, F. Caballero, SFC 201016; ibid., 2 October 2021, F. Caballero, SFC 211002; ibid., 24 October 2021, F. Caballero, SFC 211024; ibid., 17 August 2021, F. Caballero, SFC 220817; ibid., 11 September 2022, F. Caballero, SFC 220911; ibid., 9 October 2022, F. Caballero, SFC 221009; ibid., 17 September 2023, F. Caballero, SFC 230917: ibid., at the hollow base of live Platanus x hispanica , 21 May 2024, A. Valverde, SFC240521-V. Girona: Espinelves, Arborètum de Masjoan, under Aesculus sp. , 28 September 1996, J. Carbó, JC-19960928-2. Gipuzkoa: Miramon, on dead log of Populus nigra , 27 July 2007, J.I. Iturrioz, ARAN-Fungi A3008208A. Navarra: Ochovi, on piles of straw, next to cereal fields, 24 April 2015, P. Pasaban, ARAN-Fungi 01299.

Observations:—The above description is based on the collections examined for this study, with additional ecological and chorological data from the collections cited by Justo and Castro (2010).

Volvariella bombycina var. bombycina is one of the most distinctive taxa in the genus, characterized by the relatively large basidiomes, silky surface of the pileus, well-developed, sheathing volva on the stipe, and lignicolous habitat. Among the European species, V. caesiotincta shares the lignicolous habitat, but this species has smaller basidiomes with grey or brown-grey pileus that lacks short silky fibrils, and a shorter, more delicate volva that is often grey-brown. Microscopically, V. caesiotincta also has smaller basidiospores (6.9 × 4.9 μm on average) and differentlyshaped hymenial cystidia. The cells of the subhymenium in V. bombycina are rather characteristic, with prominent nodules, reminiscent of jigsaw puzzle pieces in outline. This character contrasts with the majority of Volvariella species studied here, where the subhymenium is composed of rather simple, cylindrical hyphae. Among the European species, only V. latispora has distinctive subhymenium elements, and for this reason, this character is described only in these two species.

Several varieties of V. bombycina have been described. Volvariella bombycina var. flaviceps (Murrill) Shaffer , originally described as Volvaria flaviceps from Florida, USA ( Murrill 1949) differs from V. bombycina var. bombycina (as described here) in the bright yellow colours of the pileus ( Shaffer 1957). A modern collection of V. bombycina var. flaviceps from Florida was included in the phylogenetic analyses (MES597) and its ITS does not appear to be different from V.bombycina var. bombycina ( Fig. 7 ). Volvaria palmicola Beeli , originally described from the Democratic Republic of Congo ( Beeli 1928), also has a yellow pileus and it is overall very similar to V. bombycina var. flaviceps . Shaffer (1962) recombined this taxon as V. bombycina var. palmicola , indicating the more distant lamellae and the slightly smaller basidiospores (5.9–7.5 × 4.3–5.4 μm) as the main diagnostic characters of this variety. Dennis (1961) described V. bombycina var. microspora from Venezuela, characterized also by a yellow pileus and basidiospores, 6–7.5 × 4–5 μm. It is possible that V. bombycina var. palmicola and V. bombycina var. microspora refer to the same taxon, but the relation of the two taxa to each other (and to V. bombycina var. flaviceps and V. bombycina var. bombycina ) needs to be addressed with additional modern tropical collections and molecular data. Volvariella bombycina var. ciliatomarginata Desjardin and Hemmes , has a yellow pileus like the varieties described above, but differs in the ciliate lamella edge , with cheilocystidia up to 240 μm long. This taxon is, to date, only known from Lanai Island (Hawaii, USA), growing on Araucaria ( Desjardin & Hemmes 2001) .

Figures

FIGURE 7. Best tree from the Maximum Likelihood analysis of the ITS dataset of Volvariella: detailed view of the lineage including V. volvacea and related taxa. BS ≥ 70 % and PP ≥ 0.90 are shown on or below the branches. Newly described taxa are highlighted in red.

FIGURE 8. Volvariella bombycina var. bombycina. A–F. Basidiomes. A. (ARAN-Fungi A3008208A); B. (ARAN01299); C, F. (SFC201016); D. (FG31082018-01); E. (SFC240521-V). G–M. Microscopic characters. G–H. Cheilocystidia (ARAN Fungi 01299); I. Pleurocystidium (ARAN Fungi 01299); J. Spores (ARAN FungiA3008208A); K. Subhymenium (ARAN-FungiA3043167); L. Pileipellis (ARAN Fungi A3043167); M. Volva hyphae (SFC200926). Bar: (G–K, M) = 10 μm; (L) = 100 µm. Photos by J.I. Iturrioz (A), P. Pasaban (B), F. Caballero (C, F, G–M), G. Ferisin (D) and A. Valverde (E).