Wine Roundhead

Description

The wine roundhead is a large mushroom with a cap 6–15 cm across, initially wine-brown, with time ochre to cream. It has crowded gills that darken as they mature from grey to violet-black, and a white, thick, wrinkled ring on a solid, white stem.

It grows from May to September on wood chips, straw, garden waste and humus-rich soil, mainly in parks, gardens and fields, less often in forests. In Poland it has been cultivated since 1970 and goes wild.

Distinguish it from the lacerate roundhead, which has scales on the stem and a ring that does not split; that species is probably poisonous. If you are not sure of the species, do not pick or eat it.

Identification features

Cap

Diameter 6–15 cm, even 20 cm (according to some descriptions up to 30 cm); conical-convex when young, then convex, finally spread out. Margin sharp, inrolled for a long time. Surface smooth, bare, matt, initially dark wine-brown, then lightening to ochre-brown, finally cream; sometimes cream-yellow from the start with wine-red fibrils. Dry and slippery, only slightly sticky when wet.

Hymenophore (underside of the cap)

Gills crowded, attached, initially pale grey, then grey-lilac to violet-black, with a paler edge.

Stem

Height 7–20 cm (descriptions give different ranges), thickness 1.5–3 cm, cylindrical, sometimes with a widened base, white, yellowing with age. Ring white, thick, wrinkled; its remnants may remain on the cap margin and on the stem. Surface with long fibrils, without scales. Rhizomorphs at the base.

Flesh

White, firm. Taste resembles raw potatoes. Do not taste unknown mushrooms.

Spore print and spores

Spore print violet-black (also described as dark purple-brown to black). Spores 10–14 × 6.5–8 µm.

Habitat and distribution

Ecology. Saprotroph. Grows on soil, rotted straw, wood chips and garden waste; easily cultivated on a substrate similar to the natural one. It works well as a companion to maize in the garden.

Distribution. North America, Europe, Asia and New Zealand; introduced, among other places, to Australia. In Poland a synanthropic species, expanding its range; found in parks, allotment gardens, botanical gardens, fields, less often in forests. Introduced to cultivation in Poland in 1970. An online mushroom atlas classifies it as protected and threatened, but it is not legally protected in Poland.

Fruiting. From May to September (according to some descriptions in summer and autumn).

What can it be confused with?

• Stropharia hornemannii (lacerate roundhead) — The stem has scales, the ring (if preserved) does not split, and the whole fruiting body is paler. Probably poisonous.
• Agaricus spp. (agaricus mushrooms) — The gills of agaricus mushrooms are usually pinker, in the wine cap they are grey, then violet-black; the spore print of the wine cap is dark purple-brown to black.

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

• It was introduced to cultivation in Poland in 1970.
• The species epithet rugosoannulata means "with a wrinkled ring".
• The fungus forms spiny cells (acanthocytes) with which it immobilises and digests the nematodes Panagrellus redivivus (a 2006 study).
• In English-speaking countries it is sometimes called the "godzilla mushroom", because the cap can be up to 30 cm across.