Byssomerulius corium

Description

Byssomerulius corium is a common species of crust fungus in the family Irpicaceae. It is common on the undersides of both hardwood and conifer branches. Fruitbodies are initially resupinate with a smooth, white hymenial surface. In maturity, the margin becomes reflexed and develops into a narrow, elongated white cap, and the hymenium becomes merulioid to almost poroid and cream-colored. The soft tissue and mostly resupinate fruitbodies distinguish this species from tougher Stereum species that form distinct, fan-shaped, imbricate caps.

It is a highly distributed mushroom and has been recorded in Africa, Asia, Australia, Europe, and United States.

The mycelium causes white rot. The mushroom can grow quite large, since several fruiting bodies may coalesce. Crusts of 3 to 12 cm are the rule, in rare cases, they can reach 30 cm in length.

Common names: Netted Crust, Papierzwammetje (Netherlands), Dřevokaz papírovitý (Czech Republic), Lederartiger Fältling (German), Mérule papyracée (France).

Mushroom Identification

1. Fruiting Bodies

   The fruiting bodies are spread or spread-bent, with a cap-like bent edge, 5-30 cm long, 2-4 cm wide, 0.5-6 mm thick, at first single, later often merge, thin, leathery, soft, paper-like, brittle when dry. The upper surface of the bent caps with barely noticeable zonation, smooth, slightly felty-hairy, white, whitish, grayish. The edge is sterile, bent or attached, white, pinkish-cream.

2. Hymenophore

   Wrinkled-folded, waxy, white at first, later pale pink, pale yellow, pale orange, pink-orange, red-orange, reddish, sometimes light brown. The folds are 0.3 mm wide, shallow, up to 1 mm deep, with jumpers, concentrically arranged, have the appearance of a net, with a cell density of 2-3 per 1 mm.

3. Flesh

   The flesh is 0.7 mm thick, 5 mm in bent caps, white, pale whitish.

4. Spores

   4-9 * 2-4.5 μm, elongated-oval or almost cylindrical, slightly flattened on one side and bent, with a smooth surface, with a drop, colorless.

5. Spore Print

   White.

6. Habitat

   It grows on fallen and dry trunks/branches of deciduous and coniferous trees, mainly on oaks. Causes white rot of wood. Like most of these mushrooms, it disappears from view in the summer, unless there is a very wet summer. Since August, it begins to form fruiting bodies again, which can be observed until the end of April.

Look-Alikes

1. Stereum subtomentosum

   Sometimes entirely resupinate and then similar. It is usually various shades of grayish-orange.

2. Irpex lacteus

   Has underside with jagged pores to flat teeth (microscope: encrusted cystidia).

3. Plicatura nivea

   Is a northern species on alder (Alnus).

4. Byssomerulius albostramineus

   Produces only spilled fruiting bodies and prefers the warmer part of the year.

5. Phlebia tremellosa

   Can also be similar, but it has a sterile surface of the cap often with pink shades, and is almost hairy, especially at the edge. It has thicker pulp and smaller spores.

History

In 1783 French naturalist Jean Baptiste Francois (Pierre) Bulliard described this species and named it Auricularia papyrina.

In 1967 Estonian mycologist Erast Parmasto (1928-2012) transferred this mushroom to a new genus and named it Byssomerulius corium.

The genus name Byssomerulius comes from the Latin byssus which means "fine silk-like cloth". The specific epithet corium denoting skin or fur, such as leather, refers to the re-assumed skin-like form adopted by the fruiting bodies of this species.

Synonyms and Varieties

• Thelephora corium Pers., 1801

• Auricularia papyrina Bull. (1789) var. papyrina

• Auricularia papyrina Bulliard (1788), Herbier de la France, 9, tab. 402

• Auricularia papyrina var. alba Bull. (1791)

• Auricularia papyrina var. cinerea Bull. (1791)

• Auricularia papyrina var. papyrina Bull. 1789

• Auricularia papyrina var. rubra Bull. (1791)

• Boletus purpurascens de Candolle (1815), Flore française ou description succincte de toutes les plantes qui croissent naturellement en France, Edn 3, 6, p. 41 (nom. illegit.)

• Byssomerulius confluens (Schweinitz) Lindsey & Gilbertson (1978), Bibliotheca mycologica, 63, p. 80

• Byssomerulius corium (Persoon) Parmasto (1967), Eesti NSV teaduste akadeemia toimetised. Bioloogiline seeria, 16(4), p. 383

• Byssomerulius corium f. castaneus Parmasto (1967)

• Byssomerulius corium var. corium (Pers.) Parmasto 1967

• Byssomerulius corium var. halileensis Zmitr.

• Byssomerulius sordidus (Berk. & M.A. Curtis ex Cooke) Hjortstam 1995

• Cantharellus confluens (Schweinitz) Schweinitz (1832), Transactions of the American philosophical Society, series 2, 4(2), p. 153

• Cladoderris platensis Speg., 1899

• Cladoderris rickii Lloyd (1923), Mycological writings, 7, mycological notes n° 69, p. 1196

• Meruliopsis corium (Persoon) Ginns (1976), Canadian journal of botany, 54(1-2), p. 126

• Merulius aurantiacus Klotzsch (1836), in Berkeley, The english flora of sir J.E. Smith, fungi, 5(2), p. 128 (nom. illegit.)

• Merulius chilensis Spegazzini (1924), Revista chilena de historia natural, 28, p. 26

• Merulius confluens Schweinitz (1822), Schriften der naturforschenden Gesellschaft zu Leipzig, 1, p. 92

• Merulius corium (Pers.) Fr. (1828) var. corium

• Merulius corium (Persoon) Fries (1828), Elenchus fungorum, sistens commentarium in systema mycologicum, 1, p. 58

• Merulius corium f. alutaceus Bres. (1901)

• Merulius cubensis Burt (1917), Annals of the Missouri botanical Garden, 4, p. 326

• Merulius deglubens (Berkeley & M.A. Curtis) Burt (1917), Annals of the Missouri botanical Garden, 4, p. 325

• Merulius dubiosus Bres. ex Rick, 1938

• Merulius dubiosus var. coriaceus Rick (1960), Iheringia, série botânica, 7, p. 195

• Merulius haedinus Berkeley & M.A. Curtis (1872), Grevillea, 1(5), p. 69

• Merulius hirsutus Burt (1917), Annals of the Missouri botanical Garden, 4, p. 312

• Merulius moelleri Bresadola & Hennings (1896), Hedwigia, 35(5), p. 285

• Merulius papyrinus (Bull.) Quél. (1888) var. papyrinus

• Merulius papyrinus (Bulliard) Quélet (1888), Flore mycologique de la France et des pays limitrophes, p. 32

• Merulius papyrinus var. caesius Quél. (1892)

• Merulius pelliculosus Cooke (1891), Grevillea, 19(92), p. 109

• Merulius sodiroi (Patouillard) Rick (1960), Iheringia, série botânica, 7, p. 194

• Merulius sordidus Berk. & M.A. Curtis ex Cooke, Grevillea 19: 108 (1891)

• Merulius stereoides Henn., 1901

• Merulius ulmi Peck (1906), Bulletin of the New York state Museum, 105, p. 26

• Phlebia blumenaviensis Hennings (1897), Hedwigia, 36(4), p. 198

• Phlebia deglubens Berkeley & M.A. Curtis (1891), in Cooke, Grevillea, 20(93), p. 3

• Phlebia sodiroi Patouillard (1892), Bulletin de la Société mycologique de France, 8(3), p. 116

• Polyporus eriophorus Berk. & Broome, 1882

• Polyporus purpurascens Persoon (1825), Mycologia europaea, seu complet omnium fungorum in variis europaeae regionibus detectorum enumeratio, 2, p. 60 (nom. illegit.)

• Sesia aurantiaca Kuntze (1891), Revisio generum plantarum, 2, p. 870

• Sesia confluens (Schweinitz) Kuntze (1891), Revisio generum plantarum, 2, p. 870

• Sesia corium (Persoon) Kuntze (1891), Revisio generum plantarum, 2, p. 870

• Sesia haedina (Berkeley & M.A. Curtis) Kuntze (1891), Revisio generum plantarum, 2, p. 870

• Thelephora corium Persoon (1801), Synopsis methodica fungorum, p. 574 (Basionyme) Sanctionnement : Fries (1821)

• Thelephora incarnata var. ß corium(Persoon) Persoon (1822), Mycologia europaea, seu complet omnium fungorum in variis europaeae regionibus detectorum enumeratio, 1, p. 131

• Thelephora papyrina (Bulliard) de Candolle (1805), Flore française ou description succincte de toutes les plantes qui croissent naturellement en France, Edn 3, 2, p. 106

Photo sources:

Photo 1 - Author: Valentin Hamon (CC BY-SA 4.0)

Photo 2 - Author: pinonbistro (CC BY-SA 4.0)

Photo 3 - Author: pinonbistro (CC BY-SA 4.0)

Photo 4 - Author: pinonbistro (CC BY-SA 4.0)

Photo 5 - Author: pinonbistro (CC BY-SA 4.0)