Hymenagaricus bhakkarensis A. K. Rani, A. Izhar, & Khalid, 2025

Rani, Afifa Kainat, Izhar, Aiman & Khalid, Abdul Nasir, 2025, Hymenagaricus bhakkarensis (Agaricaceae, Agaricales), a new species; and the first record of Xanthagaricus taiwanensis from Punjab, Pakistan, Phytotaxa 696 (2), pp. 117-131 : 121-124

Hymenagaricus bhakkarensis A. K. Rani, A. Izhar, & Khalid sp. nov. ( Figs. 3 , 4 )

MycoBank:—MB848347

Etymology:—the epithet “ bhakkarensis ” (Latin) refers to the type locality of this species.

Holotype:— PAKISTAN. Punjab, Bhakkar, Jinnah Park , elevation 2,575 m, on ground, mostly on grass (31° 36’ 56.1852’’ N, 71° 4’ 42.4632’’ E), elevation 159 m, July 30, 2022, Afifa Kainat Rani AK-17 ( LAH37823 , GenBank no. OQ819426 for nrITS and OQ819428 for nrLSU).

Diagnosis:— Hymenagaricus bhakkarensis is closely related to H. pakistanicus , but differs by a white to pinkish white pileal surface with a dark brown disc with many dark olive green scales, the absence of an annulus and a dark brown spore print, and hymeniform cells in the pileal squamules.

Description:— Basidiomata small. Pileus 10–24 mm diam., circular, convex to hemispherical, slightly depressed, straight margins, white to pinkish white pileal surface, disc brownish black (7.5 YR 3/2) to brown (7.5 YR 4/3), squamulose with dark olive green to dark brown (7.5 YR 3/3) scales in collection AF-06, brown (7.5 YR 4/6) at disc to light grey (7.5 YR 8/2) at periphery, with grey (7.5 YR 8/1) powdery scales in collection (AK-17), appendiculate. Lamellae subventricose, adnexed, even, regular, brownish grey (5YR, 4/1) to grey (5YR, 8/2), close, lamellulae in 2 tiers, margins concolorous. Stipe 13–25 × 1–4 mm, smooth to sometimes squamulose, central, equal, cylindrical, center hollow, base equal to sometimes slightly bulbose, surface dry, dull orange (7.5 YR 7/4) to light grey (7.5 YR 8/2), dark brown (7.5 YR, 3/3) to dark brown (7.5YR, 3/4). Annulus and volva absent. Spore print, odor and taste not recorded.

Basidiospores [40/2/2] (5.6–) 6.4–7.3 (8–) × (3.2–) 4–4.5 (–5.2) μm, avl × avw= 6.8 × 4.3 μm, Q= 1.58 μm, smooth, ellipsoid to oblong, apiculate with suprahilar depression, thick-walled, guttulate, brown to dark brown in 5 % KOH. Basidia (13–) 14–26 (–27) × (7–) 7.4–9.4 (–9.5) μm, avl × avw= 20 × 8.3 μm, clavate, hyaline in KOH, smooth, slightly thick-walled, 2–4-spored, sterigma 1.2–2.2 μm long. Cheilocystidia (25.6–) 26.8–38.8 (–41) × (5.2–) 7.4–9.3 (–10.5) μm, avl × avw= 33.0 × 8.1 μm, slightly thick-walled, clavate to subclavate, pale to brown in KOH, in clumps. Pleurocystidia absent. Pileipellis consisting of pseudoparenchymatous elements that are ellipsoidal to subglobose, clavate to subclavate, 3.6–5.8 μm, avw= 4.7 μm diam., pale to brown in 5 % KOH, branched. Stipitipellis a cutis, consisting of parallel-arranged hyphae, 2.3–5.2 μm diam., avw= 3.7 μm, hyaline, slightly thick-walled, septate, branched, overlapping arrangements. Clamp connections not observed.

Habitat:—Saprotrophic, growing in groups, in grass.

Current distribution:—Pakistan’s Plains.

Additional material examined:— PAKISTAN. Punjab, Bhakkar, Jinnah Park, elevation 2,575 m, on grass (31° 36’ 56.1852’’ N, 71° 4’ 42.4632’’ E), elev. 159 m, July 31, 2022, Afifa Kainat Rani AF-06 (LAH37824), GenBank accessions for nrITS OQ819427 and OQ819429 for nrLSU.

Xanthagaricus taiwanensis (Zhu L. Yang, Z.W. Ge, and C.M. Chen) S. Hussain , Turk. J. Bot. 42(1): 131 (2018).

= Hymenagaricus taiwanensis Zhu L. Yang, Z.W. Ge and C.M. Chen, Cryptog. Mycol. 29(3): 261 (2008) ( Figs. 5 , 6 )

Description:— Basidiomata medium, in groups of 2–3. Pileus 14–18 mm diam., convex to hemispherical, surface dry, pale yellow (25YR8/4) to 5Y (8/6) yellow, pellicle dull yellowish brown 10YR (5/3), breaking up into squamules as pileus matures except for sub-umbonate center disc, squamules becoming sparser towards margin, margin incurved. Lamellae free, pale brown (2.5Y 7/3), up to 2 mm deep, mostly crowded, 2–3 tiers of lamellulae. Stipe central, 30–75 × 0.5–0.8 mm, subcylindrical, weak at base, surface pale brown (2.5Y 7/3), concolorous with the lamellae, surface rough, densely covered with white fibrils, annulus may be present when young, not observed. Odor slightly phenolic. Taste not observed. Spore print not observed.

Basidiospores [20/2/1], (4.8–) 5–5.5 (–6.5) × (3–) 3.3–3.8 (–4.5) µm. avl × avw = 5.2 × 3.7 µm, Q = 1.22–1.7, broadly ellipsoid, yellowish brown, smooth, thick-walled. Basidia 20–35 × 6–10 µm, clavate, hyaline, 4-spored; basal cells 2-celled, sterigmata up to 3.5 μm long. Cheilocystidia (14–) 16–23 (–27) × (5.67–) 5.72–7.21 (–8) µm. avl × avw = 20 × 6.4 µm, clavate, cylindrical to flexuous, hyaline in KOH, thin-walled. Squamules on pileipellis pseudoparenchymatous epithelium, 70–90 µm, thick-walled hyphae with globose, a few ellipsoid, terminal elements, 18–40 × 16–35 µm, encrusted with brilliant brown pigment. Stipitipellis a cutis with cylindrical to subclavate, parallel, a few overlapping, thin-walled hyphae, 4.2–11.7 µm, avw = 6.9 µm, smooth, pale in KOH, rarely branched, septate. Clamp connections absent in all tissues.

Habitat and distribution:—Fruiting in groups on humus-rich soil or cattle manure, under Psidium guajava L., originally reported from Taiwan as Hymenagaricus taiwanensis ; later a new combination was proposed, Xanthagaricus taiwanensis . Previously not known from Pakistan.

Additional material examined:— PAKISTAN. Punjab, Sheikhupura district , at 236 m a.s.l., 31.7111°N, 73.9878°E, 16 July 2017, Aiman Izhar SKP13_ 2 ( LAH 35704 ; GenBank for ITS: OR335549, for LSU: OR335555 ) .

Figures

FIGURE 3. Basidiomata of Hymenagaricus bhakkarensis, A and C = AF-06 (Paratype); B, D and E =AK-17 (Holotype), Scale Bars = 10 mm. Photos by Afifa Kainat Rani.

FIGURE 4. Micromorphological characters of Hymenagaricus bhakkarensis. A–E (AK-17, Holotype): A = Basidiospores, B = Basidia, C = Cheilocystidia, D = Stipitipellis hyphae, E = Pileipellis elements. Scale Bars = A–D = 10 μm, E = 20 μm. Drawings by Afifa Kainat Rani.

FIGURE 5. Basidiomata of Xanthagaricus taiwanensis. A–H: SKP 13-2 (Holotype), Scale Bars = 10 mm. Photos by Aiman Izhar.

FIGURE 6. Micromorphological characters of Xanthagaricus taiwanensis. A–E (SKP 13-2): A = Basidiospores, B = Basidia, C = Cheilocystidia, D = Stipitipellis hyphae, E = Pileipellis elements. Scale Bars = A–E = 10 μm. Drawings by Afifa Kainat Rani and Aiman Izhar.