Kingdom: Fungi
Division: Basidiomycota
Class: Agaricomycetes
Order: Boletales
Family: Paxillaceae
Genus: Paxillus
Species: P. involutus
Binomial name: Paxillus involutus
Synonyms: Agaricus contiguous, Agaricus involutus Batsch, Agaricus adscendibus, Omphalia involute, Rhymovis involuta
Common names: Brown rollrim Brown roll-rim, Common roll-rim, Poison pax,

Paxillus involutus is a poisonous mushroom with an ectomycorrhizal symbiosis with introduced broadleaved trees such as pines (Pinus), oaks (Quercus), willows (Salix), Douglas firs (Pseudotsuga), eucalyptus, beeches (Fagus) and birches (Betula).Paxillus involutus has been inadvertently introduced to New Zealand. It occurs singly or in troops.

Paxillus involutus was previously considered edible and eaten widely in Eastern and Central Europe, it has since been found to be dangerously poisonous, after being responsible for the death of German mycologist Julius Schäffer in 1944. It had been recognised as causing gastric upsets when eaten raw but was more recently found to cause potentially fatal autoimmune hemolysis, even in those who had consumed the mushroom for years without any other ill effects. An antigen in the mushroom triggers the immune system to attack red blood cells. Serious and commonly fatal complications include acute renal failure, shock, acute respiratory failure, and disseminated intravascular coagulation. After ingested (1 -2 hours) one will develop abdominal pain, vomiting, diarrhoea, pain around the kidneys and kidney failure.

The mushrooms downy brown cap grows up to 6 cm high and has a funnel-shaped cap up to 20 cm wide with a distinctive inrolled rim and decurrent gills that may be pore-like close to the stipe.
The decurrent, ochre gills run down the stalk. 
The stout stems are up to 7 cm long, cylindrical or sometimes slightly thicker at the base, and covered with longitudinal fibrils.

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Thanks to Wikipedia for text and information: https://creativecommons.org/licenses/by-sa/3.0/