The Sickener russula, Russula emetica Fr

Russula emetica is a poisonous mushroom whose cap is mostly red but can extend from light to pale red or reddish-brown colour, it is sticky with an easily peeled film. Its gills are white and friable and free. The stalk is also white as well as its flesh which has a pungent and a very acerbic taste. The real Sickener russula mostly grows in marshy forest areas and its variety, silvestris Sing,  in other parts, particularly in oak and hornbeam woods. It grows in summer and in autumn.