Ugly Milk-Cap

Description

The ugly milk-cap has a slimy, olive-green to blackish-brown cap 5–15 cm across, with a margin inrolled for a long time and a depressed centre. The gills are cream and get dirty, and the stem is olive, paler than the cap, sometimes with pits. A damaged fruiting body exudes abundant white, very burning milk, which does not change colour in the air.

It grows from July to November in deciduous, coniferous and mixed forests, most often under birches and spruces, on acidic soils. In Poland it is common.

Its dark, olive colours usually make it easy to recognise. In Western Europe it is regarded as inedible, in the east it is sometimes salted after long soaking, but it is regarded as poisonous, because it contains the mutagenic necatorin, which cooking does not remove completely.

Identification features

Cap

Diameter 5–15 cm (4–20 cm according to some descriptions); in young specimens low and arched with the margin inrolled for a long time, in older ones spread out and depressed, finally funnel-shaped. Firm, without an umbo. Surface slimy or sticky, without zoning or with weak zoning; velvety in young ones, the margin may be shaggy. Colour from dirty olive-green to blackish-brown, darkening with age. It collects dirt, hence the "dirty" look.

Hymenophore (underside of the cap)

Gills narrow, crowded, of different lengths, slightly decurrent down the stem; at first whitish, then cream-yellow, with brown spots in old age, darkening when damaged (stained by old milk). Purple with KOH or ammonia.

Stem

Height 3–7 cm, thickness up to 2.5 cm (up to 3 cm according to some descriptions), cylindrical, at first solid, later hollow. Surface shiny when dry, slimy in the wet, sometimes rough or pitted (shallow pits). Colour from pale olive through greenish to dirty olive, paler than the cap. No ring.

Flesh

Thick, firm, white, only faintly olive under the cap skin; turns brownish in older specimens. Taste acrid, smell weak. Milk abundant, white or watery-white, does not change colour in the air, very burning. Do not taste it.

Spore print and spores

Spore print pale cream. Spores oval, with fine warts or ridges, about 7–8.5 × 6–7 µm (descriptions give different ranges).

Habitat and distribution

Ecology. Terrestrial mycorrhizal fungus; most often with birch, also with spruce, pine and other trees in mixed forests. Grows on acidic soils.

Distribution. Europe, Siberia and North America (introduced to Australia and New Zealand); in Asia reported from Japan. Common in Poland, in deciduous, coniferous and mixed forests. Not legally protected in Poland.

Fruiting. From July to November.

What can it be confused with?

• Lactarius blennius (beech milkcap) — Smaller, has a bell-shaped cap covered with banded spots, does not have such dark shades and grows under beeches.
• Lactarius olivaceoumbrinus, Lactarius atroviridis — L. olivaceoumbrinus (North America) has a more olive-brown cap and a stem with dark spots; details of L. atroviridis: no data.

Never rely on a single feature. If you are not sure — do not pick it; show the mushroom to a qualified mushroom expert.

Interesting facts

• The Latin name turpis means "ugly"; the English name "ugly milk-cap" refers to the dirty appearance of the fruiting body, which collects dirt.
• In Russia it is regarded as one of the best mushrooms for salting (without vinegar); after salting it takes on a dark cherry or burgundy colour.
• The epithet plumbeus comes from the Latin word meaning "leaden".
• The names turpis, necator and plumbeus are sometimes treated as synonyms, but Index Fungorum regards them as separate.