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Paxillus involutus

Paxillus involutus

Scientific classification
Kingdom: Fungi
Phylum: Basidiomycota
Class: Basidiomycetes
Order: Boletales
Family: Paxillaceae
Genus: Paxillus
Species: P. involutus
Binomial name
Paxillus involutus
(Batsch ex Fr.) Fr.
Paxillus involutus
mycological characteristics:
gills on hymenium

cap is depressed


hymenium is decurrent


stipe is bare


spore print is brown


ecology is mycorrhizal


edibility: poisonous

The common or brown roll-rim, Paxillus involutus, also known as the poison pax, is a mushroom previously thought to be edible with some unusual recently-discovered poisonous properties. It can cause a haemolysis which can be fatal. It often grows near edible mushrooms as well which makes it harder to identify by amateur mushroomers.



The cap, initially convex then more funnel-shaped with a depressed centre and rolled rim (hence the common name), is brown in colour and 4-10 cm wide. The narrow brownish yellow gills are decurrent and forked, darkening when bruised. It has a mild odour and taste. The spore print is brown. The stipe can be crooked and brownish or greyish yellow in colour.

Distribution and habitat

The brown roll-rim can found growing on lawns and old meadows, as well as deciduous and coniferous woodlands in Europe and North America in summer and autumn. It is an uncommon mushroom. It has been found under introduced trees in Australia.


Previously deemed edible after cooking (it can cause gastric upset when raw), Flammer in 1980 discovered an antigen within the mushroom which stimulates an autoimmune reaction causing the body's immune cells to consider its own red blood cells as foreign and attack them. This results in dangerous haemolysis, which has been fatal.[1]

The use of corticosteroids may be useful in treatment.[2]


  1. ^ Winkelmann M, Borchard F, Stangel W & Grabensee B. (1982)Fatal immunohaemolytic anaemia after eating the mushroom Paxillus involutus (author's translation from German)Dtsch Med Wochenschr. 107(31-32):1190-4 online abstract
  2. ^ Olesen LL. (1991) Poisoning with the brown roll-rim mushroom, Paxillus involutus (Translated from Danish) Ugeskr Laeger. 153(6):445
  • Breitenbach J & Kränzlin F (1991). Fungi of Switzerland 3: Boletes & Agarics, 1st Part. ISBN 3-85604-230-X. 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Paxillus_involutus". A list of authors is available in Wikipedia.
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