Leucopaxillus albissimus is a saprobic species of fungus

Fungus

A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds , as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which is separate from plants, animals, and bacteria...

 in the Tricholomataceae

Tricholomataceae

The Tricholomataceae are a large family of mushrooms within the Agaricales. A classic "wastebasket taxon", the Tricholomataceae is inclusive of any white-, yellow-, or pink-spored genera in the Agaricales not already classified as belonging to the Amanitaceae, Lepiotaceae, Hygrophoraceae,...

 family of mushroom

Mushroom

A mushroom is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground on soil or on its food source. The standard for the name "mushroom" is the cultivated white button mushroom, Agaricus bisporus; hence the word "mushroom" is most often applied to those fungi that...

s. One of the larger mushrooms in the San Francisco Bay Area

San Francisco Bay Area

The San Francisco Bay Area, commonly known as the Bay Area, is a populated region that surrounds the San Francisco and San Pablo estuaries in Northern California. The region encompasses metropolitan areas of San Francisco, Oakland, and San Jose, along with smaller urban and rural areas...

, Leucopaxillus albissimus has a fruiting body that is unusually resistant to decay.

Pileus

The cap of Leucopaxillus albissimus is 4–20 cm wide, and slowly changes from convex to becoming 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 contains a mild odor.

Lamellae

Gills are bunched together, broad, and have decurrent attachment to the stem, which runs down the stem. Although they are originally cream-colored, it turns buff-tan over the years.

Stipe

Varying from 3–7 cm in height, the stipe of Leucopaxillus albissimus is 2.5–4 cm thick, stout, and enlarged at the base. The surface of the stipe varies from smooth to finely-scaled and is a cream color when young; however, it slowly turns to buff-tan in age. When handled, it turns a bruising pale buff-brown at the base.

Spore

As with many other fungal spores, the spores of Leucopaxillus albissimus are 5–7 x 3.5–5 µm, elliptical, and ornamented with amyloid warts. In addition, Leucopaxillus albissimus has a white spore print

Spore print

thumb|300px|right|Making a spore print of the mushroom Volvariella volvacea shown in composite: mushroom cap laid on white and dark paper; cap removed after 24 hours showing pinkish-tan spore print...

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Habitat

Primarily residing under conifers and hardwoods, Leucopaxillus albimissus is often scattered and gregarious in arcs or rings. They fruit from mid to late winter.