Clitocybe rivulosa
Photo coming
Toxic lookalike
Fool's Funnel
Clitocybe rivulosa
Also small, white and full of muscarine, but its cap is flat to funnel-shaped, its gills run down the stem and its spore print is white.
White Fibercap
Inocybe geophylla
Toxic
Also called earthy inocybe, white fiber head.
The white fibercap is a small, silky white mushroom with a pointed cap and gills that turn clay brown. It grows along forest paths and lawns under trees and contains muscarine. A lilac form with the same toxin grows in the same places.
The tell
Small, silky white cap with a pointed center, over gills that turn clay brown.
Field marks
What to look at
Cap, underside and stem show in a photo. The spore print does not, and it is often the deciding check.
- Cap
- Conical to bell-shaped with a pointed bump, flattening with age. Silky white to cream, sometimes yellowing at the center, with radiating fibers. A lilac form is common.
- Underside
- Crowded gills, whitish to pale gray at first, becoming clay brown, attached to the stem.
- Stem
- White, slender and silky, with a faint cobweb-like veil when very young. No ring and no cup.
- Flesh
- Thin and white. Smell earthy or spermatic.
- Spore print
- Dull brown.
- Size
- Cap 1/2 to 1 1/2 inches (1 to 4 cm) wide; stem 1 to 2 1/2 inches (2.5 to 6 cm) tall.
Where and when
Where and when it grows
- Habitat
- Along paths, trail edges and lawns under conifers and hardwoods, often in small groups.
- Grows on
- Soil, mycorrhizal with tree roots.
- Season
- Summer through fall.
- Range
- Across North America.
Lookalikes
What the white fibercap gets confused with
Each card says how to tell the two apart.
EdibleFairy Ring Mushroom
Marasmius oreades
Grows in grass in rings, has a tan cap, widely spaced gills, a tough, bendable stem and a white spore print.
Lilac fibercap (Inocybe lilacina)
The lilac to purple form, treated as a variety or separate species. It has the same shape, habitat and toxin.
Edibility
What the field guides say
Toxic
Field guides list the white fibercap as poisonous. It contains muscarine, which causes sweating, salivation, tears, blurred vision, slowed heartbeat, vomiting and diarrhea, usually within 15 to 30 minutes. Atropine is the documented treatment. Many Inocybe species contain muscarine, and field guides treat the genus as poisonous.
This page states what field guides record. It is not advice to eat, taste or handle anything, and a photo cannot settle edibility. If someone has eaten a wild mushroom that may be toxic, call poison control (1-800-222-1222 in the US) right away, before symptoms start: the deadliest species act hours later.
FAQ
Questions about the white fibercap
Is white fibercap poisonous?
Yes. It contains muscarine, which causes heavy sweating, salivation, tears, blurred vision, slowed heartbeat and gastrointestinal upset, often within half an hour.
What are the symptoms of Inocybe poisoning?
Muscarine poisoning is sometimes summarized as the SLUDGE syndrome: salivation, lacrimation, urination, defecation, gastrointestinal upset and emesis, along with sweating and a slow pulse. Symptoms typically begin within 15 to 30 minutes.
What does the white fibercap look like?
A small, silky white mushroom with a pointed, bell-shaped cap and gills that turn clay brown. It has a slender white stem, no ring and a dull brown spore print.
Sources
Where these facts come from
- Inocybe geophylla
MushroomExpert.com
- Inocybe geophylla
Index Fungorum
Also on Mushrooms.id
Related species
Edible
Amethyst Deceiver
Laccaria amethystina
A small, entirely purple mushroom with thick, widely spaced gills and a white spore print.
Edible when cooked
Blewit
Lepista nuda
Lilac to purple gills and stem, no cobweb veil, and a pale pinkish-buff spore print.
Toxic
Poison Pie
Hebeloma crustuliniforme
Pale tan, sticky cap; in damp weather the gill edges carry tiny beads of water, and it smells of radish.
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