Stropharia rugosoannulata Farl. ex Murrill - Wine Roundhead

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Agaricales - Family: Strophariaceae

Stropharia rugosoannulata - Wine Roundhead, Wales

The Wine Roundhead is a large and very distinctive mushroom, at least when young and fresh. Unfortunately, the red-wine colouring of the caps soon fades to brown and eventually almost white in dry weather. making it more difficult to distinguish this roundhead mushroom from other dull-looking mushrooms of similar size.

The specimens shown on this page were all found in Wales, where at the time of writing (May 2014) this species is not yet formally recorded in FRDBI.

Stropharia rugosoannulata - Wine Roundhead, Carmarthenshire, Wales UK

Distribution

In Britain the Wine Roundhead is a very rare find restricted to England, at least in official records, and it is probably distributed mainly on wood chip used as garden mulch. This chunky mushroom is found only occasionally in parts of mainland Europe, whereas in North America it is widespread and very common.

Taxonomic history

When in 1922 American botanist William Alphonso Murrill (1869 - 1957) described this mushroom scientifically, drawing on an earlier description of the Wine Roundhead by fellow American William Gilson Farlow (1844 - 1919), he named it Stropharia rugosoannulata. This is still its generally accepted scientific name.

Synonyms of Stropharia rugosoannulata include Stropharia ferrii Bres.

Stropharia rugosoannulata - Wine Roundhead

Etymology

The genus name Stropharia comes from the Greek word strophos meaning a belt, and it is a reference to the stem rings of fungi in this generic grouping.

The specific epithet rugosoannulata comes from the prefix rugoso- meaning wrinkled or creased, and the suffix -annulata meaning 'with a ring'. The radially-wrinkled ring of these mushrooms is therefore the origin of the specific epithet.

Identification Guide

Cap of Stropharia rugosoannulata, Wine Roundhead

Cap

4 to 14cm across; initially bell-shaped or convex, later broadly convex or flat; when fresh the cap surface is sticky in damp weather, becoming smooth and sometimes cracking when old. The margins of young caps are sometimes hung with small remnants of the partial veil.

Cap colour is initially Burgundy-wine red to a dark reddish brown, fading to tan and eventually drying out buff, the surface sometimes developing cracks in old age.

Cut through the cap or stem and you will find firm white flesh throughout this mushroom.

Gills of Stropharia rugosoannulata, Wine Roundhead

Gills

Adnate; crowded; pale grey at first, becoming purple-brown at maturity.

Stem

10 to 18cm long and 0.9 to 2.5cm diameter; white, yellowing with age; smooth, with a large, radially grooved (not unlike a fine-toothed cogwheel) pendent stem ring; base of stem usually widens towards a clavate base. White mycelial threads (rhizomorphs) cling to the stem base when a mushroom is removed from its growing substrate.

Spores of <em>Stropharia rugosoannulata</em>

Spores

Ellipsoidal, smooth, thick-walled, 10-13 x 7.5-9µm, with a germ pore.

Show larger image

Spore print

Purple-brown.

Odour/taste

Pleasant but not distinctive.

Habitat & Ecological role

Mostly found on wood chippings spread on flower beds in parks and gardens as a mulch to suppress weeds.

Season

May to November in Britain.

Similar species

The Conifer Roundhead Stropharia hornemannii grows on pine stumps. It is a mushroom of northern Europe and in Britain is recorded only from Scotland. The Pine Roundhead does not have a rugose (wrinkled) stem ring.

The Wine Roundhead could be confused with the Goliath Webcap Cortinarius praestans, but a glance at the stem ring is all that is needed to avoid this potential problem.

Culinary Notes

Stropharia rugosoannulata is generally considered to be a good mushroom, and in the USA (where it is known as King Stropharia or Wine Cap) this species is very highly regarded; however, because the Wine Roundhead is such a rare find in Britain we do not have any first-hand experience of its culinary use.

Stropharia rugosoannulata - Wine Roundhead, on wood chip mulch

Reference Sources

Fascinated by Fungi, Pat O'Reilly 2016.

Noordeloos, M.E. (2011). Strophariaceae s.l. Edizioni Candusso: Alassio, Italy. 648 p.

Dictionary of the Fungi; Paul M. Kirk, Paul F. Cannon, David W. Minter and J. A. Stalpers; CABI, 2008

Taxonomic history and synonym information on these pages is drawn from many sources but in particular from the British Mycological Society's GB Checklist of Fungi and (for basidiomycetes) on Kew's Checklist of the British & Irish Basidiomycota.

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