Hygrophorus scabrellus A. Naseer & A.N. Khalid

Naseer, Arooj, Khalid, Abdul Nasir, Healy, Rosanne & Smith, Matthew E., 2019, Two new species of Hygrophorus from temperate Himalayan Oak forests of Pakistan, MycoKeys 56, pp. 33-47 : 38-41

Hygrophorus scabrellus A. Naseer & A.N. Khalid sp. nov. Figures 3, 4

Diagnosis.

Hygrophorus scabrellus is characterised by off-white, plano-convex pileus with greyish, dark green fibrils; yellowish-green, longer (2.1-2.4 cm) stipe with white apex and fine scales along the whole stipe; ovoid to ellipsoid, smooth and smaller (6.5 × 3.8 μm) basidiospores.

Typification.

PAKISTAN. Khyber Pakhtunkhwa Province, Swat, Toa, 2800 m a.s.l., on soil under Quercus incana , 15 July 2015, Arooj Naseer & Abdul Nasir Khalid, AST51 (holotype: LAH35245).

Etymology.

The species epithet refers to the fine scales on the stipe.

Basidiomata medium sized. Pileus 2.4-2.8 cm, creamy, off-white (7.9GY 6/1) with dark green, greyish fibrils (2.9GY 2.4/2), plano-convex, context moderately thick, margin even, smooth, incurved. Lamellae off-white to beige (4GY 6.8/2.4), subdecurrent to decurrent, thick, spaced to moderately close, L= 41-49, even, entire, undulate at margins. Lamellulae short, in two tiers, 1/3 of length of lamellae. Stipe 2.1-2.4 cm long, 0.3-0.5 cm in diameter, yellowish-green (9.3Y 4.4/2.4) with white (6.9GY 7/1) apex, finely scaled, cylindrical, slightly tapering at base, hollow.

Basidiospores [30/1/1] (4.56-) 4.72-8.1 (-8.76) × (2.5-) 2.8-5.1 (-5.2) μm, avL × avW = 6.5 × 3.84 μm, Q = (1.5-) 1.57 × 1.89 (-1.86), avQ = 1.70, white to light yellow in 5% KOH, ovoid to ellipsoid, smooth, inamyloid. Basidia 30.2-42.3 × 6.8-9.3 μm, hyaline to light green in 5% KOH, narrowly clavate, four-spored, sterigmata long (6.2-7.2 μm), medium thick-walled, densely guttulate. Hymenophoral Trama 3.7-8.2 μm in diameter, bilateral, divergent hyphae, thin-walled, branched, septate. Pileipellis 3-3.7 μm in diameter, an ixotrichoderm, composed of branched septate hyphae. Stipitipellis 3.2-7.0 μm, a thin ixocutis to ixotrichoderm, composed of compact erect hyphae. Clamp Connections present in all tissues.

Habitat and distribution.

Solitary on soil under Q. incana , at 2800 m a.s.l., in moist temperate forest of Hindu Kush Himalayan range.