Volvariella pulla E.F. Malysheva & A.V. Alexandrova, Phytotaxa

Niego, Allen Grace T., Sysouphanthong, Phongeun, Thongklang, Naritsada, Hyde, Kevin D., Phonemany, Monthien, Phookamsak, Rungtiwa & Raspé, Olivier, 2021, A new species of Volvariella and the first record of Volvariella pulla (Agaricales: incertae sedis) from Thailand, Phytotaxa 480 (3), pp. 237-250 : 244-246

Volvariella pulla E.F. Malysheva & A.V. Alexandrova, Phytotaxa 408 (4): 247 (2019)

( Figures 4 & 5 )

MycoBank MB 831060, Faces of Fungi 08024

Description:— Basidiome large. Pileus 70 mm diam., plano-convex with a low broad umbo, brownish grey (6E2) with slightly darker color at the center, dull, dry, non-hygrophanous, with fibrillose to appressed-squamulose surface; margin decurved to straight, crenulate; context light yellow (4A5), soft. Lamellae free, ventricose, close, moderately thin, soft, pale orange (6A3) to brownish orange (6C8) and turning light brown (6D8) with age; edge finely fimbriate, concolorous with faces; lamellulae present, very variable in length, mostly in one tier. Stipe 65 × 4 mm, central, terete, tapered from the base to apex, solid, dark brown (6F4–5), slightly paler near the base, entirely pubescent; context light yellow (4A5); annulus absent. Volva rather thick, mostly free, saccate, fragile, greyish brown (6D3). Spore print pinkish (7A2). Odor indistinct. Taste mild.

Basidiospores [60,1,1] (5.5)6–7–7.5(8.0) × 4–4.4–4.5(5) µm (Q = 1.2–1.8, Q* = 1.5), broadly ellipsoid to ellipsoid, oblong, ovoid, thickened wall, hyaline in 5% KOH. Basidia [30,1,1] (16)17–18.1–19(19.5) × (7)7.5–8– 8.5(9) µm (Q = 1.8–2.8, Q* = 2.3), tetrasporic, narrowly to broadly clavate, hyaline in 5% KOH. Cheilocystidia [20,1,1] (24)29–37.5–56(87) × (9)11–12.1–13(17) µm (Q = 1.6–6.4, Q* = 2.8), abundant, varied in size and shape, narrowly to broadly utriform, broadly lageniform, broadly fusiform, lecythiform, thin-walled, hyaline and colorless in 5% KOH. Pleurocystidia [20,1,1] (25)29–36.5–44(56) × (6)12–16.6–19(32) µm (Q = 1.5–4, Q* = 2.2), ellipsoid, obpyriform, utriform, broadly fusiform, lageniform, mostly thin-walled, hyaline in 5% KOH. Hymenophoral trama inverse, made up of thin-walled hyaline hyphae. Pileipellis a trichoderm; terminal elements with light brown (6D5) intracellular pigment, slightly darker on the swollen ends, [20,1,1] 77–177 × 11–31 µm. Stipitipellis a cutis; terminal elements with light brown (6D8) intracellular pigment [20,1,1] 75–162 × 8–15 µm, forming hairs. Clamp connections not seen in any part.

Habitat and distribution:—Solitary, on the soil among grasses partly covered with litter. First described from Gia Lai Province in Vietnam. Now it is also known from northern Thailand.

Specimen examined:— THAILAND. Chiang Rai Province: Mae Fah Luang University , 20.0449° N, 99.8943° E, lawn, 27 September 2018, P. Sysouphanthong, MFLU 19-1534 (GenBank MT 074696 - ITS) .

Notes:—According to the protologue, Volvariella pulla has medium to large basidiomes, with greyish brown or ash brown pileus and colored volva; the stipe is beige, ochraceous or greyish brown at base ( Malysheva et al. 2019). The specimen from Thailand is morphologically similar to the holotype. However, the stipe was darker (dark brown). This difference might be due to the more advanced maturity or drier condition of the specimen, which was photographed and described after getting back to the laboratory ( Figure 4 ).

Volvariella pulla is recorded for the first time from Thailand after it was described from Vietnam in 2019 ( Malysheva et al. 2019). Although V. pulla is morphologically most similar to V. rostricystidiata and V. volvacea , it is phylogenetically most closely related to V. guttulosa E.F. Malysheva & A.V. Alexandrova (2019: 242) and V. niveosulcata E.F. Malysheva & A.V. Alexandrova (2019: 240) ( Figure 1 ).

Figures

FIGURE 1. Phylogenetic tree generated from ML analysis of combined ITS and nrLSU data set for Volvariella with outgroup of three species of Cantharocybe and three species of Cuphophyllus. Boostrap support values (≥70%) and posterior probabilities (≥0.9) (BS/PP) are given above the branches.All terminals are with species name and voucher ID, with the newly generated sequences from this study in bold.

FIGURE 4. Mature basidiome of Volvariella pulla. (MFLU 19-1534). Scale bar = 5 cm. Photo by P. Sysouphanthong.

FIGURE 5. Microscopic features of Volvariella pulla (MFLU 19-1534). a. Cheilocystidia b. Basidiospores c. Basidia d. Pleurocystidia. e. Pileipellis terminal elements f. Stipitipellis terminal elements. Drawings by: M. Phonemany.