Yellow Stainer

Habitat

This mushroom is found in a variety of environments, including both broad-leaved and native woods, meadows, gardens, and grasslands. It frequently occurs in human-influenced or urban habitats such as lawns, roadsides, cemeteries, and wood chips. It can also be found in coastal dunes, riparian corridors, trailsides, and in deep leaf litter under specific landscape trees like the Sierra bigtree or in riparian sycamore duff. It typically grows on soil or in grassy areas, appearing as scattered individuals, small groups, or large clusters.

Photos

Appearance

Cap

5–17 cm wide; initially spherical to hemispherical with a flattened top, later becoming convex to flat. Surface is dry and white, sometimes developing fine greyish-brown scales or cracks. It stains a bright chrome-yellow immediately when rubbed or scraped, especially near the margin.

Stem

5–17 cm long and 1–4 cm thick; white and silky-smooth. It is usually equal in width but features a bulbous, sometimes crooked or lobed base. It stains bright yellow when damaged, particularly at the base.

Gills

Free from the stem and crowded. They start whitish or pale grey, transitioning to light pink, and finally becoming dark chocolate-brown to nearly black as they mature.

Flesh

Whitish, staining strikingly chrome-yellow when cut, most intensely in the base of the stem.

Ring

A prominent, white, membranous skirt-like structure on the upper stem; it is often thick with a double-layered or 'cogwheel' appearance on the underside.

Spore print

Purple-brown to dark chocolate brown.

Odor

Strong and unpleasant, reminiscent of ink, phenol, or cleaning products (like antiseptic or 'TCP'); the scent becomes more pronounced if the mushroom is heated.

Edibility

This poisonous species is the most common cause of wild mushroom poisoning in some regions because it is frequently mistaken for edible Agaricus mushrooms. Consuming it typically results in rapid-onset gastric distress, severe stomach cramps, sweating, flushing, and headaches, though not all individuals are affected. It has a distinctive unpleasant odor of ink, phenol (like TCP), or burning plastic, which may be more noticeable when cooking, and it stains bright chrome-yellow particularly at the base of the stem. It can be distinguished from safe, yellow-staining, almond-scented species by its chemical smell and its bright lemon-yellow bruising that eventually fades to a dingy gray-brown.

Nutrient Source

It obtains nutrients by breaking down dead organic matter, such as decaying plant material, in the soil.

Common Names

Basque

azpibeltz tintausain-argi, azpibeltz tintausain, azpibeltz tintausaina

Catalan

bola de neu pudent

Danish

Karbol-champignon

Dutch

Karbolchampignon

English

Yellow Stainer

French

Psalliote à peau jaune, Agaric jaunissant, Psalliote jaunissante, Agaric (psalliote) jaunissant, Agaric à peau jaune

German

Karbol-Champignon

Norwegian Bokmål

giftsjampinjong

Norwegian Nynorsk

giftsjampinjong

Spanish

champiñón amarillo, champiñón amarilleante, champiñon maloliente, champiñón maloliente, agárico amarilleante

Swedish

karbolchampinjon, giftchampinjon

Welsh

Cleisiwr Melyn

Synonyms

• Agaricus pearsonianus
• Agaricus pseudocretaceus
• Fungus xanthodermus
• Pratella xanthoderma
• Psalliota flavescens
• Psalliota grisea
• Psalliota xanthoderma