Tapinella panuoides (Fr.) E.-J. Gilbert - Oyster Rollrim

Phylum: Basidiomycota - Class: Agaricomycetes - Order: Boletales - Family: Tapinellaceae

Tapinella panuoides, Oyster Rollrim

Growing on dead conifer wood, the Oyster Rollrim usually produces overlapping tufts of fruitbodies sometimes in many tiered layers.

Distribution

An uncommon but conspicuous mushroom, the Oyster Rollrim is rather localised in Britain and Ireland. (I found the specimens shown on the left during a British Mycological Society foray in Huntingdonshire in 2013, and it was the first official county record for this species.)

Tapinella panuoides, Oyster Rollrim, Pembrokeshire

Taxonomic history

Originally described in 1818 by Swedish mycologist Elias Magnus Fries, who gave it the binomial scientific name Agaricus panuoides, the Oyster Rollrim was transferred to the genus Tapinella in 1931 by the French mycologist Édouard-Jean Gilbert (1888 - 1954).

Synonyms of Tapinella panuoides include Agaricus panuoides Fr.Paxillus panuoides (Fr.) Fr.Paxillus fagi Berk. & BroomePaxillus panuoides var. fagi (Berk. & Broome) Cooke, Paxillus panuoides var. ionipes Quél., and Paxillus panuoides var. rubrosquamulosus Svrcek & Kubicka.

In line with the British Mycological Society's taxonomic system (and Kew Gardens/Index Fungorum), we have placed the Tapinella genus in the family Tapinellaceae.

Tapinella panuoides, Oyster Rollrim, on sawdust, North Pembrokeshire

Etymology

Tapinella as a mushroom genus was established in 1931 by the French mycologist Édouard-Jean Gilbert (1888 - 1954).Tapinella comes from Tapis, meaning a carpet. The specific epithet panuoides means 'similar to a Panus species' (see Panus rudis, for example), and Panus means a swelling or tumour. (In their early development these mushrooms look like roundish tumour-like growths emerging from the substrate timber.)

In autumn 2014 I came across the group of Oyster Rollrims seen above and on the left in North Pembrokeshire. The growing substrate was sawdust, thought to have been from shredded Alder saplings.

By sheer coincidence (see my comment about the Huntingdonshire find pictured at the top of this page), this was the first official record of Tapinella panuoides in the county of Pembrokeshire.

Identification guide

Tapinella panuoides, underside view

Cap

Oyster shaped with an eccentric attachment; inrolled margin; surface initially finely downy, sometimes breaking into small scales when old; golden-brown; 1 to 8cm across.

Gills

Decurrent, crowded, branching; bright yellowish buff, turning browner when bruised.

Stem

Absent or very rudimentary; laterally attached.

Spores of Tapinella paunoides, Oyster Rollrim

Spores

Ellipsoidal, smooth, 5-6.5 x 3-4.5µm.

Spore print

Reddish-brown.

Odour/taste

Not distinctive.

Habitat & Ecological role

Saprobic, on decaying conifer timber.

Season

Autumn in Britain and Ireland.

Similar species

Paxillus involutus, the Brown Rollrim, has brownish gills that darken when bruised.

Culinary Notes

The Oyster Rollrim mushroom is reported to be inedible.

Tapinella panuoides, Oyster Rollrim, on conifer timber, Huntingdonshire

Reference Sources

Fascinated by Fungi, Pat O'Reilly, 2011

BMS List of English Names for Fungi

Mattheck, C., and Weber, K. Manual of Wood Decays in Trees. Arboricultural Association 2003.

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.

Other web pages about this species

Michael Kuo (USA)

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