Pleurocybella porrigens

What You Should Know

Pleurocybella porrigens is a small, thin, white-fleshed fungus that decomposes wood. This mushroom associated with conifers (particularly Tsuga, the hemlocks), and more specifically, a white-rot fungus (in general, these digest lignin in wood and leave cellulose behind, though they can also digest both - but lignin is less abundant, so it can give the appearance of leaving cellulose behind).

In older field guides, this species — which looks a lot like a small oyster mushroom — is listed as edible and good. In more recent guides, this mushroom is accompanied by the warning: not recommended for eating. And according to many credible sources today, the Angel Wing is considered poisonous.

In Fall 2004, 59 people in 9 prefectures of Japan were sickened by Pleurocybella porrigens. Seventeen died of acute encephalopathy. All or nearly all of the deaths involved people with compromised kidneys and the average age of the victims was 70. No previous reports are known of poisoning by Pleurocybella porrigens.

Other names: Angel’s Wings, Kridthat (Danish), Korvavinokas (Finnish), Pleurote Étalé (French), Ohrförmiger Seitling (German), Żagiew Łuskowata (Polish), Hlivec Biely (Slovak), Hlíva Ušatá (Czech Republic), Öronmussling (Swedish), Krittostersopp (Norwegian), Sugihiratake (Japanese).

Pleurocybella porrigens Mushroom Identification

1. Cap

   1.5–10 cm in diameter, shape vase-like and open on one side, tongue-like, or ear-shaped. Maybe fan-shaped when growing on the side of a log. Caps gradually narrow towards the base. The cap is white to ivory, thin-fleshed, and translucent. The surface is smooth. The flesh is pliable. As caps expand sideways, consistent with their common name, they sometimes look like angel wings.

2. Gills

   Rather crowded, narrow, and covering the entire undersurface of the mushroom, white.

3. Stem

   Virtually absent.

4. Spores

   5–7.5 x 4–6 µm, smooth.

5. Habitat

   Often in troops and clusters, on coniferous wood, often on western hemlock (Tsuga heterophylla), on fallen tree trunks, and stumps in coastal coniferous forests. Saprotrophic.

6. Geographical range

   Widespread in the boreal and northern parts of North America and Eurasia. Reported from Alaska southwards into northern California.

Pleurocybella porrigens Look-Alikes

Various species of Crepidotus, Hohenbuehelia, and Panellus are similar in appearance but are inedible or of unknown edibility. They differ most obviously in that they are relatively small (under 6 cm broad) and not generally as white.

The edible Pleurotus populinus differs in that the cap is whitish but not ivory white, the flesh is thicker, and it fruits in the spring on aspens and cottonwoods.

Pleurocybella porrigens Taxonomy and Etymology

This oyster-like mushroom was first described validly in the scientific literature in 1805 by Christiaan Hendrik Persoon, who established its basionym when he gave it the binomial name Agaricus porrigens. It was German-born American mycologist Rolf Singer who, in transferring it to the genus Pleurocybella in 1947, established its currently-accepted scientific name. Pleurocybella is a very small genus with just five species currently (January 2017) known to exist; it was established by Rolf Singer in 1947.

Synonyms of Pleurocybella porrigens (Pers.) Singer include Agaricus porrigens Pers., Calathinus porrigens (Pers.)., Pleurotellus porrigens (Pers.), and Pleurotus porrigens (Pers.) P. Kumm.

The latter two names reflect the macroscopic similarity of Angel's Wings to Oyster mushrooms Pleurotus ostreatus and relatives.

The genus name Pleurocybella comes from the Greek Pleuron, meaning side by side.

The specific epithet porrigens is Latin and means extending or stretching out horizontally.

Sources:

Photo 1 - Author: 2011-10-21_Pleurocybella_porrigens_177980.jpg: (Creative Commons Attribution-Share Alike 3.0 Unported)

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

Photo 3 - Author: BlueCanoe (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 4 - Author: Jerzy Opioła (Creative Commons Attribution-Share Alike 3.0 Unported)

Photo 5 - Author: Katja Schulz from Washington, D. C., USA (Creative Commons Attribution 2.0 Generic)