Caballero, Justo & Teres, 2025

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 : 59-61

19. Volvariella globifera F. Caballero, Justo & Teres , sp. nov. ( Fig. 27 ).

MycoBank: MB 856536

Typification:— Holotype: SPAIN. Guipuzkoa, Zumaia, Zuloaga park, 43°17’56.10’’N, 2°14’50.43’’W, elev. 6 m, on sandy soil (tertiary dune) under Cupressus macrocarpa , 17 September 2017, J. Teres , ARAN-Fungi 09431!

Etymology:—From the Latin “ globus ” ball, globe, sphere and “- fer ” carrying, by its characteristic globose or subglobose elements in the pileipellis.

Diagnosis:— Volvariella globifera is characterized by its small, fragile basidiome, pileus fibrillose with discrete squamules, white to slightly yellowish in older specimens, and translucent, white stipe and the presence of subglobose elements in the pileipellis. Molecularly, is most closely related to V. taylorii , but the nrITS sequences of both species have more than 40 individual differences.

Description:— Pileus 10–20 mm diam., convex or conico-convex when young, expanding to plano-convex, with a low, broad umbo; surface densely fibrillose, fibrils often grouped in small squamules, hygrophanous, white overall, sometimes with subtle yellow or yellow-brown tints; margin smooth or slightly striate, slightly exceeding the lamellae, and irregular. Lamellae moderately crowded, free, broadly ventricose, white when young, becoming salmon pink or pinkish brown with age; edge entire or slightly irregular, concolourous. Stipe 20–40 × 2–6 mm, cylindrical, slightly widening towards the base, straight or slightly curved; surface white, sometimes translucent, finely pubescent. Volva membranaceous, saccate, white, with 2–3 lobes. Rhizomorphs not observed. Context white, thin, smell indistinct.

Basidiospores (n=134, c=1) 4.6–7.3 × 3.3–4.6 μm, avl × avw = 5.8 × 3.9 μm, Q = 1.20–1.81, avQ = 1.46, broadly ellipsoid to oblong, thick-walled, with barely distinct hilar appendage. Basidia 22–35 × 7–10 μm, tetrasterigmate, clavate or subcylindrical. Lamella edge sterile. Cheilocystidia common, (33–)45–57(–69) × (8–)12–22(–30) μm, most fusiform with an elongated apex, some clavate, lageniform or utriform. Pleurocystidia scarce, 29–61 × 9–32 μm, similar to cheilocystidia. Pileipellis a cutis or cutis-trichoderm, with terminal elements 8–25 μm wide, often constricted at the septa, with hyaline contents, intermixed with elements 63–121 × 28–55 µm, often globose or subglobose, but also sausage-shaped, broadly fusiform, or pyriform. Stipitipellis a cutis, or a cutis-trichoderm, with cylindrical hyphae, 3–11 μm wide. Volva composed of interwoven, cylindrical hyphae, 3–19 μm wide, some with common septa and some without septa. Clamp connections absent in all parts examined.

Habit, habitat, and phenology:—Gregarious. Terrestrial, on sandy soil under Cupressus macrocarpa . September.

Distribution:—Only known from the holotype collection.

Observations:— Volvariella globifera is morphologically very similar to all other small, white Volvariella species, including V. pusilla , V. hypopithys , V. latispora , V. ranulicystis , and V. reidii (see Tables 1 and 2). Molecularly, it is not closely related to any of these taxa, but instead appears as the sister taxon to V. taylorii ( Fig. 3 ), a species with predominantly grey pileus.

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 27. Volvariella globifera (ARAN-Fungi 09431, holotype). A. Basidiomes. B–I. Microscopic characters. B–C. Cheilocystidia; D. Pleurocystidia; E. Spores; F. Pileipellis; G–H. Intermediate cells of the pileipellis; I. Volva hyphae. Bar: (B–I) = 10 µm. Photos by J. Teres (A), F. Caballero (B–I).