Romell initially thought the fungus might be Climacocystis borealis, but ultimately rejected that opinion, as that species has an easily breakable fruit body, and its spores are of different size and shape.

[5] The fungus has microscopic characteristics that are typical of the genus Tyromyces, but differs by the presence of thick-walled amyloid cystidia in the hymenium.

Individual fruit bodies measure up to 15 cm (6 in) wide, and have a dirty whitish to light buff surface colour that becomes reddish brown when dry or if bruised.

[8] Oligoporus fragilis is similar in appearance, but can be distinguished microscopically from Amylocystis lapponica by the lack of amyloid cystidia.

Several conditions are required to support local populations, including: "vegetative continuity (never cut), natural tree species composition, multi-aged structure, rich presence of dead wood in various stages of decay, relatively large area of virgin forest surrounded by near-natural forest, and a stable, cold and humid meso- and microclimate."

[10] In contrast to its rarity in Central and Southern Europe, A. lapponica is known from hundreds of localities in Finland and Sweden, and dozens in Norway.

[11] In both the Czech Republic and Poland, where it is considered critically endangered, the fungus is found on their Regional Red Lists and as such is protected by law.