Large White Leucopax

Leucopaxillus albissimus

"Leucopaxillus albissimus", commonly known as the large white leucopaxillus, is a species of mushroom that lives as a saprobe, decaying the litter under coniferous trees. It produces a large white fruiting body that is unusually resistant to decay. It is considered to be inedible.
Leucopaxillus albissimus  Fall,Geotagged,Leucopaxillus albissimus,United States

Appearance

The species is generally white, with "albissimus" meaning 'whitest' in Latin.

The cap of "Leucopaxillus albissimus" is 4–20 cm wide, and slowly changes from convex to plane; occasionally the disc is depressed. When young, the margin is incurved and faintly striate. The cap's surface is dry, unpolished, and smooth; in moderate weather, it becomes scaled and a shade of cream to cream-buff. As it ages, the cap's surface turns buff-tan. Overall, the flesh is white, moderately thick, and has a mild odor. Gills are crowded, broad, and decurrent. Although they are originally cream-colored, the gills turn buff-tan with age. Varying from 3–7 cm in length, the stipe of "Leucopaxillus albissimus" is 2.5–4 cm thick, stout, and often enlarged at the base. The surface of the stipe varies from smooth to finely-scaled and is a cream color when young; it may turn buff-tan in age. When handled, it bruises pale buff-brown at the base.

"Leucopaxillus albissimus" has a white spore print. The elliptical spores are ornamented with amyloid warts. The spores measure 5–7 x 3.5–5 µm.

While the biological reason for the trait is unknown, the species demonstrates a tendency not to rot.
large white leucopaxillus  Fall,Geotagged,Leucopaxillus albissimus,United States

Naming

"Leucopaxillus gentianeus" is closely related. "Clitocybe" species may appear similar due to the decurrent gills.

Habitat

Primarily residing under conifers and hardwoods, "Leucopaxillus albimissus" is often scattered or gregarious in arcs or rings. It fruits from mid to late winter in California, and in autumn in other parts of North America.

References:

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Taxonomy
KingdomFungi
DivisionBasidiomycota
ClassAgaricomycetes
OrderAgaricales
FamilyTricholomataceae
GenusLeucopaxillus
SpeciesL. albissimus