[2] Molecular analysis of DNA sequences confirms its genetic uniqueness, and its status as sister species to H. aurantiaca.

[4] Hygrophoropsis rufa can have a penetrating ozone-like smell, reportedly reminiscent of an orchid species Oncidium ornithorhynchum or a photocopier.

These hyphae are of three types: broad, thick-walled and hyaline (translucent); filiform (threadlike); or with granular golden-brown contents.

In contrast, the cap cuticle of H. aurantiaca is arranged as a uniformly tangled cutis (with hyphae parallel to the pileus surface).

[5] A rare species, H. rufa has been recorded in the United Kingdom, Austria, Germany, and Denmark, although unconfirmed internet photos suggest a wider range that includes France and Slovakia.