Russula nigricans - Blackening Brittlegill

Taxonomy

Phylum: Basidiomycota

Class: Agaricomycetes

Order: Russulales

Russula nigricans, the Blackening Brittlegill, is a very variable species in terms of its size, shape and colour: it changes in each of these respects quite markedly as it matures, eventually becoming black all over.

Although considered edible when young, Russula nigricans becomes tough when older and is particularly prone to maggot infection; it is also prone to attack by parasitic fungi such as Asterophora parasitica.

Identification Guide

The widely-spaced adnate gills are an important identifying feature of this very common member of the Russulaceae, which is frequently confused with other large, pale brittlegills and milk caps.

Russula nigricans sometimes produces fairy rings; the picture on the left is part of such a ring. It is commonly referred to as the Blackening Russula.

	Cap 6 to 20cm (exceptionally 25cm) in diameter, convex with an inrolled margin and then later flatter and centrally depressed, the caps are dirty white at first, turning grey-brown and then eventually blackening all over. Below the cap cuticle, which often cracks in dry weather, the flesh is white, greying with age.
	Gills The well-spaced adnate gills are thick. Straw-coloured at first (as in the young specimen illustrated here), the gills soon turn grey and bruise rosy red-brown when damaged. Eventually, like the rest of the fruiting body, the gills turn dull black. Stem 1 to 4cm in diameter and 3 to 8cm tall, the smooth, blackening stems are cylindrical or taper in slightly towards the base. The stem flesh is white at first, blackening with age or when bruised. There is no stem ring.
Spore print	White.
Odour/taste	Slight fruity odour; mild taste becoming hotter after a few moments.
Habitat	Coniferous and broad-leaf woodland.
Season	July to November.
Occurrence	Common.
Similar species	Russula densifolia is found mainly under beech trees; it has crowded gills and turns black without an intermediate brown stage.