Pseudomerulius aureus

On dead wood and bark of conifers, especially Pinus (this collection on Pinus sylvestris wood in direct contact with the ground), with resupinate to slightly effused-reflexed basidiomata, with a merulioid, rugose hymenophore featuring interconnected, anastomosing radial folds, vivid lemon-yellow to golden-orange, soft and waxy when fresh.

Hyphal system monomitic; hyphae cylindrical, 1.5 to 3.5 µm wide, containing brown intracellular pigment, branched, interwoven, slightly separated by gelatinization, septate and partly clamped.

Cystidia and other sterile hymenial elements absent.

Basidia cylindrical-clavate, 15 to 25 µm long, 3 to 4 µm wide, clamped at the base, 4-spored.

Spores small, cylindrical, smooth, hyaline, thin-walled, 3.5 to 4.5 µm long, 1.5 to 2 µm wide, lacking a distinct apiculus, containing minute oil droplets, inamyloid in Melzer's reagent.

The folded-merulioid hymenophore, bright yellow colour, and small cylindrical spores are diagnostic for the species.

Herbarium material available: JTP2106/24.