Winecork brittlegill or Ugly milk cap

The cap is 5–15 cm across, occasionally up to 20. It starts convex, then flattens, develops a dip in the centre and in old specimens becomes almost funnel-shaped.

Young caps are dirty white or greyish buff, then grey-brown and smoky brown, and dark brown to blackish in old mushrooms. The surface is smooth, slightly sticky and shiny when damp, and the margin is even, without grooves.

The cap is 6–15 (up to 20) cm across, making this a large, fleshy milk cap. It starts convex with an inrolled, fuzzy margin, then flattens and finally becomes funnel-shaped with a sunken centre. The colour is dark olive, olive-black or brownish-black; young caps have a yellow-green tinge, old ones are almost black. In wet weather the surface is very sticky and slimy; in dry weather it's shiny, with darker concentric zones. In young mushrooms the margin is densely downy.

The gills are narrow and of unequal length, with many short ones in between, sometimes forked, and attached to the stem or running slightly down it. They start white, turn greyish, and darken where pressed. Sources describe the gills as both close and widely spaced, so don't rely on spacing.

The spore print is white.

The gills are crowded, narrow, adnate or slightly decurrent, pale yellow to cream, taking on a dark olive tinge with age. Where damaged they darken to brown or black, a characteristic reaction. They exude white milk. The spore print is cream.

The stem is 3–6 cm tall, up to 11 cm in large specimens, and 1–3 cm thick. It is hard, cylindrical and smooth, the colour of the cap but paler, and it darkens when handled. The base is often massive, wrinkled and folded.

There is no ring, no volva and no veil remnants.

The stem is 3–8 cm tall and 1–3 cm thick, cylindrical or thickening toward the base, solid when young and often hollow later. It's paler than the cap, olive-yellow to dingy olive, often with characteristic dark “scrobicules” (sunken pits). It's also sticky in wet weather. There's no ring and no volva.

The flesh is white, firm and hard. When broken it slowly turns faintly pink over half an hour, then pale smoky grey, but never black as in the blackening brittlegill. There is no milk. The taste is mild and sweetish, sometimes slightly sharp.

The flesh is whitish to yellowish and firm, slowly darkening to grey-brown when cut. Any damage releases plenty of white milk that doesn't change colour in the air but leaves dark stains on the mushroom. With alkali (KOH) it turns violet-black, another diagnostic feature.

The smell is noticeable and distinctive: musty, like an old empty wine cask, and some describe it as mouldy. This is what gave the mushroom its English name.

The smell is faint, neutral, slightly resinous; old mushrooms can smell dirty and earthy. Raw, the flesh and milk taste extremely acrid, bitter and hot. Do not taste it raw.