Xanthagaricus montgomeryensis N. Fatima, & Khalid, 2023

Fatima, Nadia & Khalid, Abdul Nasir, 2023, Xanthagaricus montgomeryensis sp. nov. (Agaricaceae, Agaricales) from Chichawatni Forest, Punjab Pakistan, Phytotaxa 594 (4), pp. 256-266 : 259-261

Xanthagaricus montgomeryensis N. Fatima, & Khalid sp. nov. ( Figures 1 , 2 )

MycoBank MB845151

Etymology:—The specific epithet “ montgomeryensis ” refers to the District Montgomery (now Sahiwal), the type locality.

Diagnosis:— Xanthagaricus montgomeryensis differs from its closely related species X. thailandensis by having pale-yellowish pileus (20–30 mm) with pale to yellowish brown squamules, small oblong to ellipsoid basidiospores (3.99–4.87 × 2.12–2.85 µm), absence of caulocystidia, and turning brown on bruising or cutting of basidiomata.

Holotype:— PAKISTAN. Punjab: Sahiwal, Chichawatni, Forest 30° 32’ 16”N, 72° 40’ 4”E, alt. 168 m, on plant debris as saprotrophs under Bombax cieba L., 27 September 2020, Nadia Fatima , N-339A, (Holotype LAH37434 ), GenBank OP150139 (ITS) and OP150142 (28S).

Description:— Basidiomata small to medium-sized and gregarious. Pileus 20–30 mm diam., broadly parabolic when young, hemispherical to plane with age, slightly depressed at the center, surface dry, pale yellowish (7.5Y 8/3) at the young stage with a large dark brown (7.5Y 3/4) squamule at the center, disrupting into small scattered yellowish brown (10Y 5/8) squamules towards the margin, brown (2.5YR 5/8) on cutting. Lamellae gray (5YR 7/2), free, even, densely crowded, regular with 1–2 tiers of lamellulae. Stipe 50–60 × 3–4 mm, equal, central, solid, slightly curved at base, surface white, smooth, without squamules when young, context white becoming brown (2.5YR 5/8) when cut and bruised. Annulus superior, membranous, white. Volva absent, thick, dark brown rhizomorphs present. Taste and odor not recorded.

Basidiospores [50/3/3] (3.94–)3.99–4.87(–4.91) × (2.06–)2.12–2.85(–2.96) µm, (avl × avw =4.35 × 2.47 µm), Q = 1.65–1.93 µm, avQ = 1.75 µm smooth, oblong to ellipsoid, without germ pore, inamyloid, slightly thick-walled, light pale in 5% KOH. Basidia smooth, 13.77–18.62× 5.02–6.52 µm, clavate, hyaline, 2 or 4-spored, thin-walled, hyaline in 5% KOH. Cheilocystidia varying in shape from clavate to broadly clavate, sometimes ventricose, 12.36–24.64 × 5.34–9.04 µm, smooth, thin-walled, abundant, hyaline in 5% KOH. Pleurocystidia absent. Squamules of pileipellis are composed of pseudoparenchymatous cells of varying shapes, globose to subglobose, oblong, sometimes subclavate, 8.43–21.72 × 6.72–12.83 µm, slightly thick-walled, smooth, without incrustations, hyaline to pale brown in 5% KOH. Pileipellis hyphae are irregular, branched, smooth, thin-walled, 2–8.6 µm wide, hyaline in 5% KOH. Stipitipellis a cutis composed of thin-walled hyphae 3.16–14.48 µm, smooth, branched, hyaline in 5% KOH. Clamp connections absent in all tissues.

Habit and Habitat:—Gregarious, saprotrophic on plant debris under Bombax cieba tree, in Chichawatni Forest.

Additional Specimens Examined:— PAKISTAN. Punjab: Sahiwal, Chichawatni Forest 30° 32’ 16”N, 72° 40’ 4”E, alt. 168 m, on plant debris as saprotrophs, 14 July 2021, Nadia Fatima N-340, LAH! LAH37435. GenBank OP150140 (ITS) and OP150143 (nuLSU). 30°31’35.86”N, 72°39’2.37”E, elev. 166 m, on soil, 02 August 2021, Nadia Fatima N-339B, LAH! LAH37436. GenBank OP150141 (ITS).

Figures

FIGURE 1. A–D. Basidiomata of Xanthagaricus montgomeryensis. A= Pileus view (LAH37434, Holotype), B–D= Lamellae & Stipe view (Paratype). Scale Bars A–D = 5 mm. Photos by: Nadia Fatima.

FIGURE 2. A–D. Anatomical structures of Xanthagaricus montgomeryensis (Holotype, LAH37434) A. Basidiospores, B. Basidia, C. Cheilocystidia, D. Pileal squamules. Scale Bars: A–B. 3µm, C–D 4µm. Photos by: Nadia Fatima