Tapinella panuoides

What You Should Know

Tapinella panuoides is a fungus species in the genus Tapinella. This inconspicuous wood rotter is characterized by a dull ochre-brown, often shallowly-lobed cap, wavy intervenose gills, and a conifer fruiting habit. Because of its nondescript appearance, it is sometimes confused with several other gilled, shelf fungi.

Despite its pleasant taste, the species is poisonous.

Other names: Fan Pax, Stalkless Paxillus, Oyster Rollrim.

Tapinella panuoides Mushroom Identification

1. Ecology

   Saprobic; growing alone or gregariously on woodland conifer wood and lumber; summer and fall (also overwinter in warmer climates); widely distributed in North America.

2. Cap

   3-8 cm; fan- or shell-shaped; planoconvex; dry; finely velvety when young, but sometimes becoming bald with age; tan, yellow-brown, or orangish brown; the margin inrolled at first, often with a somewhat scalloped appearance.

3. Gills

   Close; dull orangish to yellowish; frequently forked, cross-veined, crimped, or corrugated, especially near the base.

4. Stem

   Absent, or present only as a small lateral extension.

5. Flesh

   Whitish or dirty yellowish; not changing when sliced.

6. Odor and Taste

   Not distinctive.

7. Spore Print

   Yellowish-brown or brownish.

8. Microscopic Features

   Spores 3.5-5 x 2.5-4 µ; ellipsoid; smooth; hyaline and uniguttulate in KOH; frequently dextrinoid. Hymenial cystidia not found. Pileipellis a cutis of hyaline-in-KOH elements 2.5-5 µ wide.

Tapinella panuoides Look-Alikes

1. Phyllotopsis nidulans

   Can be distinguished by a hardwood habit, apricot-orange, pubescent cap, straight, not wavy gills, and skunk odor.

2. Lentinellus ursinus

   Has a dull-brown, similarly-shaped cap but has gills with serrulate edges and an unpleasant taste.

3. Hygrophoropsis aurantiaca

   Distinguished by a more centrally attached stipe and distinctly forked, bright-orange gills.

4. Tapinella corrugata (Paxillus corrugatus)

   Is similar to this species. The gills often differ in color but the potential exists for confusion.

5. Paxillus involutus

   Has brownish gills that darken when bruised.

Tapinella panuoides Medicinal Properties

1. Free-radical scavenging activity/neuroprotective effects

   Two p-terphenyl compounds, identified as leucomentin-4 and leucomentin-2 were isolated from methanolic extract of the fruit body of Paxillus panuoides.

   These compounds strongly inhibited lipid peroxidation in rat liver microsomes with IC50 values of 0.10 and 0.06 µg/ml, respectively (Yun et al., 2000). It was later suggested the neuroprotective effect that the leucomentins have is due to their ability to chelate iron (when present with DNA and H2O2), thus inhibiting iron-mediated oxidative damage to DNA (Lee et al., 2003).

2. Hemagglutination activity

   Purified lectins from T. panuoides extracts were able to hemagglutinate human red cells, with an anti-A specificity. The reaction of anti-A agglutinin was strongly inhibited by N-acetyl-D-galactosamine (Furukawa et al., 1995).

3. Antitumor activity

   Several of the p-terphenyl ortho-quinones described above were found to be active in assays against tumor cell cultures (Cali et al., 2004).

Tapinella panuoides Taxonomy and Etymology

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. & Broome, Paxillus panuoides var. fagi (Berk. & Broome) Cooke, Paxillus panuoides var. ionipes Quél., and Paxillus panuoides var. rubrosquamulosus Svrcek & Kubicka.

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', and Panus means a swelling or tumor.

Sources:

Photo 1 - Author: Ron Pastorino (Ronpast) (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 2 - Author: Strobilomyces (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 3 - Author: Richard Kneal (bloodworm) (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 4 - Author: Richard Kneal (bloodworm) (Creative Commons Attribution-Share Alike 3.0 Unported)