Postia guttulata
Basidiocarps: annual, sessile or effused-reflexed, dimidiate, imbricate, up to 10 cm wide and 10-20 mm thick; sterile surface rough, radially fibrillose, whitish to yellowish ochraceous, with roundish, small depressions; margin thin, undulate and inflexed when dry. Pore surface: whitish with yellowish tints; pores round-angular, 4-6 per mm. Flesh: white, 2-5 mm thick, taste very bitter. Hyphal system: monomitic, generative hyphae hyaline, thin to thick-walled, branched, 3-5.5μm wide, up to 10-12μm in the context; gleoplerous hyphae present, sinuous and swollen; cystidia absent, fusoid cystidioles present. Basidia: clavate (club shaped), hyaline with a basal clamp, 13-22 x 4-6 μm. Spores: hyaline, no colour change in IKI (Lugol's iodine), smooth, thin-walled, oblong to sub-cylindrical, 4-4.5(5) x 2-2.5 μm.
Found on the wood of conifers including Picea (spruce) and Cedrus (cedar).