Volvariella volvacea (Bull.) Singer, 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 : 49-52

14. Volvariella volvacea (Bull.) Singer, Lilloa 22: 401. 1951 [“1949”] var. volvacea . ( Fig. 22 )

≡ Agaricus volvaceus Bull., Herbier de la France 6: Tab. 262. 1786, nom. sanct. (Fr., Systema Mycologicum 1: 278. 1821) [basionym]

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

≡ Volvariopsis volvacea (Bull.) Murrill , North American Flora 10(2): 144. 1917

See observations below for some possible heterotypic synonyms such as:

1. Volvariella bakeri (Murrill) Shaffer, Mycologia 49(4): 557. 1957 (≡ Volvariopsis bakeri Murrill, Mycologia 3(6): 281. 1911 [basionym])

2. Volvariella diplasia (Berk. & Broome) Singer, Lilloa 22: 401. 1951 [“1949”] (≡ Agaricus diplasius Berk. & Broome, Transactions of the Linnean Society of London 27(2): 151. 1870) [“1871”] [basionym])

3. Volvaria ilicicola Speg., Anales del Museo Nacional de Buenos Aires, Ser. 3, 10: 114. 1908

Typification status:— Lectotype, designated here [icon]: Agaricus volvaceus in Bull., Herbier de la France 6: Tab. 262, Fig. A (between figures B and C). 1786. MycoBank type: MBT 10023152.

No type specimen exists. The French specimen G00295827 collected in a greenhouse (nrITS GenBank accession number PP660654 ) by M. Josserand is chosen here as the reference specimen for V. volvacea var. volvacea .

Description:— Pileus 40–80 mm diam., ovoid when young, expanding to conico-convex, plano-convex in older specimens, with a low broad umbo; surface fibrillose, with fibrils reaching and exceeding the pileus margin, rather dark grey, grey-brown at centre, much paler towards margin, not hygrophanous; margin not striate, irregular and exceeding the lamellae. Lamellae crowded, free, broadly ventricose, white when young, becoming salmon pink or pinkish brown with age; edge entire, or punctuated by white areas. Stipe 40–90 × 5–10 mm, cylindrical, slightly widening towards bulbous base, straight; surface white, smooth or pubescent with minute hairs. Volva membranaceous, saccate, externally white, to dark grey or grey-brown, with 3–4 lobes, with a velvety texture, with attached mycelial cords (rhizomorphs). Context white with earthy smell.

Basidiospores (n=61, c=1) 6.6–8.7 × 4.6–6.1 μm, avl × avw = 7.4 × 5.3 μm, Q = 1.16–1.64, avQ = 1.39, broadly ellipsoid to ellipsoid, thick-walled, with barely distinct hilar appendage. Basidia 26–35(–40) × 9–11 μm, tetrasterigmate, clavate or subclavate. Lamella edge heterogeneous. Cheilocystidia common, (44–)70–84(–109) × (10–)20–35(–37) μm, utriform, lageniform, clavate, often with a narrowed apex and pedunculate. Pleurocystidia scarce, 42–75 × 8–31 µm, scattered, similar to cheilocystidia. Pileipellis a cutis or an intermediate cutis-trichoderm, with terminal elements, (4–)7–29(–31) μm wide, often constricted at the septa; hyaline or with intracellular or vacuolar pigment, pale brown or olive-brown. Stipitipellis a cutis or a cutis-trichoderm in the upper part of the stipe, with cylindrical hyphae, 5–19 μm wide. Volva composed of interwoven, cylindrical hyphae, 5–15 μm wide, with common septa; on the external surface arranged as a trichoderm. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Often gregarious. In Europe growing on compost, sawdust, often in greenhouses, associated with accumulations of organic matter. In the tropics also recorded growing directly on wood. Fruiting all year around.

Distribution:—In Europe, known with certainty from France. Widely cultivated in the tropics.

Additional collections examined:— DOMINICAN REPUBLIC. Puerto Plata, Sosua, growing gregariously on piles of leaves and woody debris in a coastal forest near the beach, 6 November 2023, C . Angelini, ANGE1889 ; ibid., growing gregariously on a dead broadleaf trunk in a cemetery, 28 November 2023, C . Angelini, ANGE1932 . FRANCE. Lyon: Parc de la Tête d’Or, inside the warm greenhouses, on sand, and on fir sawdust, 6 April 1938, M . Josserand, G00295827 .

Observations:—The above description is based on that of V. volvacea by Josserand (1959), our own observations on the collection G00295827 by the same author, and two additional collections from the Dominican Republic that molecularly match the sequences of V. volvacea included in the phylogenetic analyses. The reference specimen and the Dominican collections fit the original and modern descriptions ( Shaffer 1957; Orton 1974, 1986; Pegler 1977, 1983; Boekhout 1990; Kosonen 2012) well.

Volvariella volvacea var. volvacea is characterized by a distinctly innately fibrillose pileus (with dark grey, grey-brown fibrils), a dark grey-brown volva, medium-sized spores (averaging over 6 μm in length), often narrowly lageniform (with elongated apical neck) hymenial cystidia, and in Europe the occurrence in greenhouses or on garden refuse (sawdust, compost or spent tan).

This species is widely cultivated in the tropics for human consumption, and is commonly called the ‘paddy straw fungus’ or ‘straw mushroom’ ( Heim 1947; Singer 1961; Horak 1968; Chang & Yau 1971; Orton 1974, 1981; Heinemann 1975; Pegler 1977, 1983; Liu et al. 2020; Somrau et al. 2021). The records of this species in Europe might represent introductions as they are often associated with greenhouses or similar environments (e.g., Bulliard 1786; Josserand 1959; Horak 1968; Orton 1974, 1986; Lazzari & Cadonici 1982; Krieglsteiner 1984; Boekhout 1990; Kosonen 2012).

All the sequenced collections (including the reference specimen) named as V. volvacea var. volvacea and the collection CBS355_64 (as V. diplasia ) form a clade that is sister to a clade consisting V. bombycina and two sequences of V. orientalis from Vietnam ( Fig. 7 ). Volvariella bombycina differs from V. volvacea by the whitish to yellowish cream, straw yellow silky-fibrillose to squamulose-villose pileus surface, a pale cream to pale brown volva ( Shaffer 1957; Orton 1974, 1986; Boekhout 1990; Kosonen 2012). Volvariella orientalis differs in its pilose-squamulose pileus, ochre brown or olive brown volva and the presence of caulocystidia (Malysheva & Popov 2022).

A large number of varieties (or undefined infraspecific epithets), other than the autonym variety of V. volvacea , have been described, some under the genus Agaricus or Volvaria :

1. Agaricus volvaceus (unranked) minor Bull., Herbier de France 7: Tab. 330. 1788

2. Agaricus volvaceus var. rhodomelas (Lasch) Fr., Epicrisis Systematis Mycologici : 138. 1838 (≡ Agaricus rhodomelas Lasch, Linnaea 4: 548. 1829, nom. sanct. [Fr., Systema Mycologicum 3, Index: 39. 1832]; ≡ Volvaria rhodomelas (Lasch) P. Kumm., Der Führer in die Pilzkunde: 99. 1871)

3. Volvaria volvacea var. fennica (P. Karst.) Sacc., Sylloge Fungorum 11: 43. 1895 (≡ Volvaria virgata var. fennica P. Karst., Hedwigia 30: 246. 1891)

4. Volvaria volvacea var. edulis Overeem , in Heyne, De Nuttige Planten van Nederlandsch-Indië (ed. 2) 1: 72. 1927 [nom. nov. for Pholiota moschocaryana Overeem ] (≡ Pholiota moschocaryana Overeem, De Nuttige Planten van Nederlandsch Indië 1, Herdruck: 10. 1922 [as “(Streintz) V. Overeem, nov. comb. ”; A validly published name by reference to the description of Boletus moschocaryanus in Rumphius, Herbarium Amboinense 6: 124. 1750; Art. 38.11])

5. Volvariella volvacea var. nigricans Hongo , The Journal of Japanese Botany 38: 233 (1963) (– Volvaria volvacea var. nigricans Kawam., Icones of Japanese Fungi 5: 596. 1954; nom. inval., nom. nud. Art. 39.1, no Latin diagnosis)

6. Volvariella volvacea var. lignicola M. Kaur & Y. Singh, Proceedings of 8th International Conference on Mushroom Biology and Mushroom Products ( ICMBMP8 ) 1: 64. 2014; nom. inval. Art. 40.6. Typification without the words type or holotype or their equivalent in a modern language .

In all cases these names are frequently considered synonyms of V. volvacea var. volvacea in mycological literature and therefore they have fallen into disuse and they have been not (or hardly) used after their original publication.

The most similar European species are V. caesiotincta and V. taylorii . Volvariella caesiotincta is distinguished by a pileus often with bluish tinges, smaller spores, hymenial cystidia with an abruptly connected, irregular, branched-tosubcoralloid rostrum ( Orton 1974, 1986; Antonín 2012; Kosonen 2012). Volvariella taylorii differs from V. volvacea in having a smaller pileus, smaller spores, cystidia without a highly elongated apical neck, and growing mainly in coastal forests, in sandy or grassy areas in dune ecosystems (see above and, e.g., Shaffer 1957; Orton 1974; 1986; Boekhout 1986, 1990; Seok et al. 2002; Niveiro et al. 2017). Volvariella nigrovolvacea was originally described from grassy fields in the Czech Republic ( Kosina 1974), and in addition to the habitat, it differs from V. volvacea in the larger basidiomes (pileus 100–150 mm diam.) and slightly smaller cheilocystidia (47–70 × 13–18 μm). Other than spore size and cheilocystidia, no other microscopic characters are given in the original description of V. nigrovolvacea , so it is very difficult to establish its identity.

Among the extra-European taxa, the neotropical V. cubensis (Murrill) Shaffer (1957: 564) , originally described from Cuba ( Murrill 1911) and later also reported from Guadalupe in the Antilles ( Pegler 1983), Brazil ( Wartchow 2009), southern India ( Adnaan-Farook et al. 2013) and Mexico ( Hernández-Del Valle et al. 2019) has smaller spores, nonmucronate hymenial cystidia, and is terrestrial on humus ( Shaffer 1957, Pegler 1983, Wartchow 2009, Hernández-Del Valle et al. 2019). Volvariella bakeri (Murrill) Shaffer (1957: 557) , originally described from Cuba, is morphologically very similar to V. volvacea var. volvacea ( Pegler 1983, 1986). Volvariella diplasia (Berk. & Broome) Singer (1951: 401) from Sri Lanka ( Ceylon), is cultivated locally, and also produces chlamydospores in culture ( Rangaswami 1956; Heinemann 1975) just as V. volvacea var. volvacea . Volvariella diplasia has been considered a white variant of V. volvacea var. volvacea ( Heinemann 1975) or V. bombycina ( Dennis 1961) . Additionally, Dennis (1961) considered Volvaria ilicicola Speg. (1908: 114) a putative synonym of V. diplasia . In the phylogenetic analysis ( Fig. 7 ), the collection named V. diplasia (viz., CBS355.64, from India) clusters with V. volvacea var. volvacea .

II: Newly described European taxa.

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 22. Volvariella volvacea var. volvacea. A–D. Basidiomes. A–B. (ANGE 1932); C–D. (ANGE1889). E–M. Microscopic characters. E–F. Cheilocystidia, E. (ANGE1889), F. (G00295827); G. Pleurocystidium (ANGE1889); H–I. Spores, H. (ANGE 1889), I. (G00295827); J–K. Pileipellis (ANGE1889); L. Volva hyphae (ANGE1932); M. Stipitipellis (ANGE1889). Bar: (E–L) = 10 µm; (M) = 100 µm. Photos by C. Angelini (A–D), F. Caballero (E–M).