Volvariella griseoalba Arshad, Ijaz & Jabeen

Arshad, Wasiqa, Ijaz, Hira, Khan, Mehboobullah, Yasmeen, Aneela, Zhao, Chang-Lin, Ghafoor, Aneeqa, Komal, Eisha, Niazi, Abdul Rahman & Jabeen, Sana, 2024, Volvariella griseoalba (Agaricales, Volvariellaceae), a new species from Punjab, Pakistan, Phytotaxa 661 (1), pp. 31-46 : 39-42

Volvariella griseoalba Arshad, Ijaz & Jabeen , sp. nov. ( Figures 4–5 )

MycoBank:—MB851273

Etymology:—The specific epithet refers to its greyish-white pileus color.

Diagnosis:—Differs from V. sathei by its shiny greyish-white umbonate pileus, subglobose to broadly ellipsoid basidiospores, utriform cheilocystidia and a white to brown volva.

Holotype:— Pakistan, Punjab, Mianwali District, Jinnah Barrage, at 210 m a.s.l., on soil, 17 July 2023, Mehboobullah Khan , 25-S32 ( UEHF0010 ); GenBank accession: OR886619 ( ITS) and OR886620 ( LSU).

Description:—Pileus 4.5–6.3 cm in diameter, convex to applanate at maturity, slightly umbonate, center light pink (5RP 9/3); surface delicately fibrillose; margin plicate striate; light pink (5RP 9/3) from center to white towards the margins; context shiny greyish-white. Lamellae free, close; margin entire; pink (5RP 8/4). Lamellulae frequent, of variable lengths. Stipe 7–9.2 × 0.8–1 cm, central, slightly broad from apex (1.2 cm) and base (1–1.5 cm); surface fibrillose; shiny white. Volva 3.2–3.5 × 2.3–2.9 cm; saccate, irregularly lobed; white to brown (10YR 9/4) from outside, inner side light pink (5RP 9/3).

Basidiospores [40/2/2] (5.2) 5.7–7.2 (7.4) × (4.6) 5.2–6.5 (7.1) µm, Q = 1–1.3, avQ = 1.2, subglobose to broadly ellipsoid, apiculus prominent, thick walled, guttulate, hyaline to greenish in 5% KOH. Basidia (21.5) 23.5–31.4 (34) × (10) 10.1–12.8 (13) µm, clavate to rarely fusiform, 2–4 spored. Cheilocystidia (51.5) 51.8–62 (63.5) × (18.5) 19.5– 24.4 (25) µm, abundant, variable shapes, clavate to broadly fusiform, narrowly utriform with basal cells, triangular to conical. Pleurocystidia (20) 23.7–26.9 (28.8) × (8.6) 9.5–11 (12.5) µm, extremely variable in size and shape, broadly clavate to utriform, mucronate to fusiform, septa at base. Pileipellis (9.5) 9.7–11.8 (11.9) µm wide, cutis type, terminal cell broad (15.8 –16 µm), cylindrical, intricate or irregular trichoderm, branched, septate. Stipitipellis (5.5) 7.5–9.9 (11.3) µm wide, intricate trichoderm, septate. Clamp connections absent in all tissues and hyaline in 5% KOH.

Habitat and distribution:—On soil, xerophytic vegetation of Mianwali District, Punjab, Pakistan. Additional material examined:— Pakistan, Punjab, Lahore District, Lahore, Botanical Garden, University of the

Punjab, at 217 m a.s.l., solitary on soil, 25 July 2022, Aneeqa Ghafoor, Eisha Komal and Abdul Rehman Niazi, BG-1

(LAH25722!); GenBank accession: OR146496 (ITS).

Figures

FIGURE 4. Volvariella griseoalba. A–D. UEH-F0010; E. LAH25722. Scale bars A–D = 1 cm. Photographs by Mehboobullah Khan (A–D) and Abdul Rehman Niazi (E).

FIGURE 5. Volvariella griseoalba (UEH-F0010). A. Basidiospores; B. Basidia; C. Cheilocystidia; D. Pleurocystidia; E. Pileipellis; F. Stipitipellis. Scale bars: A–F = 10 µm.