''Leucopaxillus albissimus'' is a species of

mushroom A mushroom or toadstool is the fleshy, spore-bearing fruiting body of a fungus, typically produced above ground, on soil, or on its food source. ''Toadstool'' generally denotes one poisonous to humans. The standard for the name "mushroom" is t ...

that lives as a

saprobe Saprotrophic nutrition or lysotrophic nutrition is a process of chemoheterotrophic extracellular digestion involved in the processing of decayed (dead or waste) organic matter. It occurs in saprotrophs, and is most often associated with fungi ( ...

, decaying the litter under

coniferous trees Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...

. It produces a large white fruiting body that is unusually resistant to decay. It is considered to be inedible.

Description

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

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

. The

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

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 Flesh is any aggregation of soft tissues of an organism. Various multicellular organisms have soft tissues that may be called "flesh". In mammals, including humans, ''flesh'' encompasses muscle Skeletal muscles (commonly referred to as mu ...

is white, moderately thick, and has a mild odor.

Gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

are crowded, broad, and

decurrent ''Decurrent'' (sometimes decurring) is a term used in botany and mycology to describe plant or fungal parts that extend downward. In botany, the term is most often applied to leaf blades that partly wrap or have wings around the stem or petio ...

. 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 300px, Making a spore print of the mushroom ''Volvariella volvacea'' shown in composite: (photo lower half) mushroom cap laid on white and dark paper; (photo upper half) cap removed after 24 hours showing pinkish-tan spore print. A 3.5-centimeter ...

. The elliptical

spores In biology, a spore is a unit of sexual or asexual reproduction that may be adapted for dispersal and for survival, often for extended periods of time, in unfavourable conditions. Spores form part of the life cycles of many plants, algae, f ...

are ornamented with

amyloid Amyloids are aggregates of proteins characterised by a Fibril, fibrillar morphology of 7–13 Nanometer, nm in diameter, a beta sheet (β-sheet) Secondary structure of proteins, secondary structure (known as cross-β) and ability to be Staining, ...

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. Leucopaxillus albissimus spores

Habitat

Primarily residing under

conifer Conifers are a group of conifer cone, cone-bearing Spermatophyte, seed plants, a subset of gymnosperms. Scientifically, they make up the phylum, division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single ...

s 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.

Similar species

'' Leucopaxillus gentianeus'' is closely related. ''

Clitocybe ''Clitocybe'' is a genus of mushrooms characterized by white, off-white, buff, cream, pink, or light-yellow spores, gills running down the stem, and pale white to brown or lilac coloration. They are primarily saprotrophic, decomposing forest grou ...

'' species may appear similar due to the decurrent gills.

References

{{Taxonbar, from=Q6534177 Fungi described in 1873 Fungi of North America Inedible fungi Taxa named by Charles Horton Peck Tricholomataceae