It is found exclusively under oak trees in Europe, where it grows solitarily or in scattered groups in autumn months.

[1] The specific epithet quietus means "quiet" or "calm", and is possibly used to refer to the unintrusive colours of the cap.

incanus was described by Lexemuel Ray Hesler and Alexander H. Smith in their 1979 North American species of Lactarius.

[5] Lactarius quietus typically has a convex cap of 5 to 8 centimetres (2.0 to 3.1 in) across, which later flattens or develops a small depression in the centre.

In colour, the cap is a dull reddish brown with a tint of cinnamon, sometimes with darker concentric bands or spots.

[8] The brownish-white gills are slightly decurrent, and change colour with age to a pale reddish brown with mauve hints.

incanus is typically slightly larger than the nominate variety, and younger specimens feature a whitish bloom, after which the variant is named.

[5] Lactarius quietus is found growing exclusively at the base of oak trees,[13] solitarily or in scattered groups, in soil.

[15] L. quietus can be found only in Europe; in the United Kingdom, it is one of the one hundred most commonly encountered mushroom species.