Foetid Russula

Description

The Foetid Russula is a large russula with a cap up to several centimetres across (over ten), yellow-brown or brownish, slimy in wet weather and shiny in dry weather. The cap margin is distinctly grooved. The gills are cream-yellowish, brown-spotted with age, and often covered with droplets in young fruiting bodies. The stem is thick, yellowish-white, rust-spotted at the base, and hollow inside in older fruiting bodies.

It grows from July to September in deciduous and coniferous forests, under many tree species. In Poland it is common.

It is easiest to recognise by its smell: strong, unpleasant and suffocating, resembling rotting vegetables. The similar Russula subfoetens (Polish: gołąbek niemiły) can be hard to tell apart by appearance, so if in doubt, do not collect it for eating.

Identification features

Cap

Diameter 7–15 cm (descriptions give different ranges, some up to 10 cm); hemispherical and very slimy when young, later flat and spreading, slightly depressed in the centre. Colour yellow-brown, honey-yellow to ochre-brown. The cuticle is slimy when wet, dry and shiny in dry weather, and can be peeled back up to 2/3 of the cap diameter. Margin with comb-like grooves.

Hymenophore (underside of the cap)

Gills crowded, later more distant, up to 14 mm wide; pale cream-yellowish, later ochre-yellowish and spotted brown, often weeping droplets in young fruiting bodies.

Stem

Height 7–12 cm, thickness 2–3.5 cm, cylindrical, yellowish-white or spotted yellow-brown, rust-spotted at the base. Initially firm and solid, with age hollow inside and divided into chambers.

Flesh

White, turning brown in the stipe, rigid and compact. Smell strong, unpleasant and suffocating (resembling rotting vegetables, and in old fruiting bodies also fishy). Taste unpleasant, acrid; the flesh should not be tasted. When damaged it discolours fairly quickly, especially in young fruiting bodies, turning pale lemon in the cap and rusty in the stipe.

Spore print and spores

Spore print cream to pale cream. Spores broadly ellipsoid, covered with conical, blunt-tipped warts, rarely connected by ridges; 6.5–9.7(11.5) × 5.5–7.7(8.5) µm.

Habitat and distribution

Ecology. Mycorrhizal fungus, growing on the ground. Observed under maples, silver birch, hornbeam, beech, larch, spruce, pine, poplar, pedunculate oak, rowan and lindens.

Distribution. Northern Hemisphere on all continents, in the Southern Hemisphere only in Australia. In deciduous and coniferous forests. Common in Poland. Not legally protected in Poland.

Fruiting. In Poland from July to September.

What can it be confused with?

• Russula subfoetens (Polish: gołąbek niemiły) — Morphologically it can be indistinguishable. It is smaller and grows only in deciduous forests; its smell is less repulsive and its taste much less acrid. With KOH or NaOH it turns golden (the Foetid Russula turns cream). It also differs in microscopic features.
• Russula pectinatoides (Polish: gołąbek przykry) — The Foetid Russula is easily distinguished by its slimy cap and unpleasant smell.
• Russula illota (Polish: gołąbek brudny) — The Foetid Russula is easily distinguished by its slimy cap and unpleasant smell.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The Polish name of the species was given by Feliks Berdau in 1876; it was formerly also called "serojeszka śmierdząca".
• The smell of the Foetid Russula is compared to rotting vegetables, and in old fruiting bodies to fish.
• Adult Tritoma angulata beetles have been recorded on the fruiting bodies, although they do not seem to feed on it regularly.
• It is distinguished from Russula subfoetens (Polish: gołąbek niemiły) among other things by its reaction with potassium or sodium hydroxide: cream in the Foetid Russula, golden in R. subfoetens.