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Page number:435 
Remarks (public):The identity of this taxon has been confused in the past because of reports of the existence of two morphologically indistinguishable species, one a bitter-tasting brown rot fungus and the other a non-bitter white rot fungus. The brown rot fungus was considered by Lowe and Lombard (1973) to be Tyromyces lacteus and the supposed white rot fungus to be T. tephroleucus. However, no substantive evidence for such a fungus causing a white rot has ever been presented. We agree with the conclusion of Redhead and Ginns (1985) and David (1980) that a single brown rot species is involved. The application of the epithet tephroleucus seems to be well founded. There has also been some confusion with the taxon recognized as Tyromyces chioneus (Fr.) Karst., previously often called Polyporus albellus Pk. 
Description type:Non-original description 
Description:Oligoporus tephroleucus (Fr.) Gilb. & Ryvarden - Mycotaxon 22:365, 1985. - Polyporus tephroleucus Fr., Syst. Mycol. 1:360, 1821. -Polyporus lacteus Fr., Syst. Mycol. 1:359, 1821.
Basidiocarps annual, sessile or effused-reflexed; pileus up to 2 cm wide; upper surface cream-coloured to mouse-grey, coarsely strigose; pore surface whitish when fresh, yellowish on drying, the pores 3-4 per mm, dissepiments thin and finely lacerate; context whitish, usually concentrically zonate, up to 1 cm thick; tube layer white to cream coloured, brittle on drying, up to 8 mm thick.
Hyphal system monomitic; contextual hyphae thin- to moderately thick-walled, abundantly nodose-septate, some with frequent branching, 3-8 µm in diam, some thin-walled hyphae staining brightly in phloxine; tramal hyphae mostly thin-walled, with clamps, 2-4 µm in diam.
Cystidia or other sterile hymenial elements absent; hyphal pegs present. Basidia clavate, 4-sterigmate, 14-16 x 4-5 µm, with a basal clamp.
Basidiospores cylindric, slightly curved, hyaline, smooth, negative in Melzer' s reagent, 4.5-6 x 1-1.5 µm.
Type of rot. Brown cubical rot of dead conifers and hardwoods.
Cultural characteristics. See Lowe and Lombard (1973, as Tyromyces lacteus). The cultural description given by Stalpers (1978) is based on Tyromyces chioneus, a white rot fungus.
Sexuality. Heterothallic and bipolar.
Substrata. Occasionally on conifers like Abies, Larix, Picea, and Pinus, usually on hardwoods like Acer, Alnus, Betula, Castanea, Corylus, Cratageus, Fagus, Frangula, Fraxinus, Juglans, Malus, Populus, Prunus, Pyrus, Quercus, Salix, Sorbus, Tilia and Ulmus.
Distribution. Widely distributed in forest ecosystems of Europe and north to 70° N in Norway. Circumpolar in the boreal coniferous ecosystem.
Taxon name: