Volvariella terrea Musumeci & A. Riva, Schweizerische Zeitschrift

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 : 47

13. Volvariella terrea Musumeci & A. Riva, Schweizerische Zeitschrift für Pilzkunde 85(2): 68. 15 April 2007. ( Fig. 21 ).

= Volvariella aethiops A. Favre & Vialard , Bulletin Mycologique et Botanique Dauphiné-Savoie 184: 23. 26 December 2007 Typification status:— Holotype: France, Rixheim, in grass under broadleaved trees, 1 October 2005, E. Musumeci, LUG11010 !

Description:— Pileus 20–80 mm in diam., ovoid when young, expanding to conico-convex, convex, plano-convex in older specimens, with or without a distinct central umbo; surface densely tomentose-fibrillose to lanate, covered with fibrils that sometimes group to form minute squamules all over; fibrils reaching and exceeding the pileus margin, giving it an irregular aspect; grey, brown-grey; 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 irregular, white and floccose, or concolorous and more or less even. Stipe 70–80 × 5–10 mm, cylindrical, slightly widening towards the base, straight or curved; surface grey, paler than pileus, smooth, or with grey-black fibrils, sometimes grouped in squamules. Volva membranaceous, saccate, white to grey-brown, with 2–4 lobes; rhizomorphs not observed. Context white or grey-white with earthy or slightly Pelargonium smell.

Basidiospores (n=179, c=2) 5.9–9.9 × 3.8–5.6 μm, avl × avw = 6.8 × 4.3 μm, Q = 1.25–2.15, avQ = 1.57, broadly ellipsoid to cylindrical; thick-walled, with barely distinct hilar appendage. Basidia 19–34 × 7–10 μm, tetrasterigmate, clavate or subclavate. Lamella edge heterogeneous. Cheilocystidia common, (33–)64–121(–190) × 13–24(–42) μm, clavate, broadly clavate, lageniform or fusiform, sometimes mucronate or with 1–2 apical nodules. Pleurocystidia scarce, 33–130 × 24–32 µm, similar to cheilocystidia, mostly clavate. Pileipellis a cutis or an intermediate cutis-trichoderm, with terminal elements, 5–32 μm wide, often constricted at the septa, with diffuse intracellular pale brown pigment, sometimes with granular intracellular black pigment. Stipitipellis a cutis or a cutis-trichoderm in the upper part of the stipe, with cylindrical hyphae, 7–23 μm wide. Volva composed of interwoven, cylindrical, septate hyphae, 5–26 μm wide; some individual elements with granular pigment. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Gregarious. In grasslands or in grassy areas under broad-leaved trees ( Carpinus , Fagus , and Quercus ), fruiting among basidiomes of Agaricus xanthodermus . October–December.

Distribution:—Known from England, France, Italy and Spain. Outside Europe also recorded from Oregon ( USA).

Additional collections examined:— FRANCE. Haute Savoie: Thonon-Les-Bains, in a meadow with abundant Thymus serpyllum next to Agaricus xanthodermus , 14 October 2006, A. Gruaz, G53946 (holotype of V. aethiops ). ITALY. Venezia: Parco di Mestre, among grass next to A. xanthodermus , 8 December 2022, A. Refellato, A. Camoli & D. Alzani, RCA08122022. SPAIN. Girona: Pla de Castanyers, les Planes d’Hostoles, in a grazing meadow, next to Agaricus xanthodermus , 22 October 2014, J. Montón, JM2912.

Nomenclatural comments:—No molecular differences were observed between the holotype collections of V. aethiops and V. terrea . Both names were published in the same year but V. terrea has priority over V. aethiops because the former was published on 27 April 2007 as pointed out in the heading of issue two above the summary, and the latter on 26 December 2007 as pointed out in the last page of the subsequent number (188) for the year 2008 by the statement “ le précédent numéro a été publié le 26 décembre 2007 ”.

Observations:— Volvariella terrea is characterized by having a tomentose-lanose pileus surface, a grey pileus, stipe and context, and especially by growing next to Agaricus xanthodermus . Musumeci and Riva (2007) suggest that the association of V. terrea with Agaricus xanthodermus is indicative of a parasitic relation. While no definitive proof of the relation being parasitic yet exists, it should be noted that the holotype of V. aethiops (described independently and shown here to be a synonym of V. terrea ) was also collected next to Agaricus xanhodermus , as were the two additional collections from France and Spain studied by us.

Volvariella glaucocephala is another grey-capped species fruiting among basidiomes of Agaricus , although in the case of V. glaucocephala it is A. arvensis , not A. xanthodermus . For a detailed comparison see under V. glaucocephala .

Other species with a grey pileus occurring in Europe are V. caesiotincta , V. dunensis , V. murinella , V. taylorii , and V. volvacea but none of these species are associated with Agaricus species. Other morphological differences are summarized in Tables 1 and 2.

Figures

FIGURE 21. Volvariella terrea. A, B, D. Basidiomes of V. terrea. C. Basidiomes of Agaricus xanthodermus (left) and V. terrea (right) together.A–D. (LUG11010, holotype). E–K. Microscopic characters (JM2912). E–F. Cheilocystidia; G. Pleurocystidium; H. Pileipellis; I. Spores; J. Volva hyphae; K. Stipitipellis. Bar: (E–K) = 10 µm. Photos by E. Musumeci (A–D), F. Caballero (E–K).