''Russula nigricans'', commonly known as the blackening brittlegill or blackening russula, is a gilled mushroom found in woodland in Europe. It gains both its common and scientific name from its propensity to turn black from cutting or bruising.

Taxonomy

It is placed in the ''Compactae'' group, subsection ''Nigricantinae'' by

Bon ''Bon'', also spelled Bön () and also known as Yungdrung Bon (, "eternal Bon"), is a Tibetan religious tradition with many similarities to Tibetan Buddhism and also many unique features.Samuel 2012, pp. 220-221. Bon initially developed in t ...

. It was first described by the French mycologist Pierre Bulliard in 1798 as ''Agaricus nigricans'', before gaining its current binomial name from the father of mycology, the Swedish mycologist Elias Magnus Fries. Its specific epithet is the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

''nigricans'' 'blackening'.

Description

This is a large member of the genus ''

Russula ''Russula'' is a very large genus composed of around 750 worldwide species of ectomycorrhizal mushrooms. They are typically common, fairly large, and brightly colored – making them one of the most recognizable genera among mycologists and mushr ...

'', and it has a

cap A cap is a flat headgear, usually with a visor. Caps have crowns that fit very close to the head. They made their first appearance as early as 3200 BC. Caps typically have a visor, or no brim at all. They are popular in casual and informal se ...

that is dirty white when young, but swiftly turns brown, and then black on aging. It measures in diameter. There is usually a large depression in the centre of mature caps, which are three quarter peeling. The stem is white, firm, and straight, measuring long and wide; it too blackens with age. The

gills A gill () is a respiratory organ that many aquatic organisms use to extract dissolved oxygen from water and to excrete carbon dioxide. The gills of some species, such as hermit crabs, have adapted to allow respiration on land provided they are ...

are off-white initially, very widely spaced, and are adnate. These turn red; then grey, and finally black, when bruised. The flesh, which has a fruity smell, when cut turns pale Indian red, and then grey, and black within 20 minutes. The

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is white, and the warty oval spores measure 7–8 x 6–7 μm. Old specimens are sometimes parasitised by fungi of the genus '' Asterophora'' or ''Nyctalis'', in particular the species ''N. parasitica'' and ''N. asterophora'' (the pick-a-back toadstool).

Distribution and habitat

''Russula nigricans'' appears in late summer and autumn in both deciduous and coniferous woodland across Britain, Northern Europe, and at least the East Coast of North America.

Toxicity

The species contains toxins which could cause gastrointestinal upset.

Similar species

Species that also bruise red then black include '' Russula acrifolia'' and ''R. dissimulans''. '' Russula albonigra'' has closer gills and is far less common. It bruises directly to black, lacking the red intermediary phase.

References