False Charcoal Burner

Russula grisea Fr.

1 Observations

1 week ago Last Observed

The False Charcoal Burner (Russula grisea) is a medium to large brittlegill with a smooth, shiny cap in shades of greyish-violet, violet and olive, 5-11 cm across, convex when young and becoming depressed. The gills are crowded, pale yellow and brittle, and the stem is white.

It grows from Jun to Oct in broadleaf woodland, mycorrhizal with sweet chestnut, beech, oak and lime. It is widespread but uncommon in the UK.

It is easily mistaken for the Charcoal Burner (Russula cyanoxantha), which has greasy, flexible gills that rarely fork, whereas R. grisea has brittle gills that often fork. Other grey, violet or green-capped brittlegills, such as Russula parazurea and Russula ionochlora, can also look similar and often need microscopic features to separate them. The taste ranges from mild to acrid, and as the species cannot safely be told from its relatives in the field, it should not be eaten.

Spore Print

Season

Native

unknown

Distribution

Widespread but uncommon

Habitat

Mycorrhizal with sweet chestnut, beech, oak and lime in broadleaf woodland, on clay or calcareous soils.

Etymology

Russula comes from the Latin russus, meaning red, with a diminutive ending, so "reddish". It refers to the red caps of many brittlegills. The specific epithet grisea comes from Medieval Latin griseus, meaning grey, and refers to the grey tones of the cap.

Associates

Castanea, Fagus, Quercus, Tilia

Cap

The cap surface is smooth and shiny, with greyish-violet, violet and olive tones that often blend together. It is convex at first and becomes depressed with age.

Colour
Shape	convex, depressed
Surface	smooth
Width	5 - 11 cm
Peeling	1/2

Gills

The gills are thin, very brittle and often forking. They are sometimes tinted rose-violet near the cap margin.

Colour
Spacing	crowded

Flesh

White, firm and brittle. The taste is mild, though it can be slightly acrid in young gills.

Odour	Not distinctive
Taste	Mild, acrid

Stem

The stem is firm, stocky and rather short. It is white, but is sometimes tinted lilac in parts.

Colour

Macrochemicals

Iron sulphate (FeSO4) turns the flesh bright rust, and guaiac turns it blue.

FeSO₄
Guaiac

Spores

The spores are subglobose and warty, with warts up to 1.25 µm high. There are few thick connectives or chains of warts joining them.

Colour
Shape	subglobose
Ornamentation	warty
Size	6.5-8 x 5.5-6.5 μm

Microscopic Features

The gill edge has pointed, spindle-shaped cells. The hyphae of the cap surface are cylindrical with thread-like terminal cells. The cap-surface cystidia are cylindrical or club-shaped with a terminal appendage.