Oudemansiella mucida

Oudemansiella mucida

The porcelain fungus (Oudemansiella mucida (Schrad.) Höhn., 1910) is a fungus belonging to the Physalacriaceae family.

Systematics –
Domain Eukaryota,
Kingdom Fungi,
Division Basidiomycota,
Subdivision Agaricomycotina,
Class Agaricomycetes,
Subclass Agaricomycetidae,
Order Agaricales,
Family Physalacriaceae,
Genus Oudemansiella,
Species O. mucida.
Synonyms include:
– Collybia mucida Quél.;
– Mucidula mucida (Schrad.) Pat.

Etymology –
The name Oudemansiella was given in honor of the Dutch mycologist Cornelis van Oudemans (or Oudeman), often combined with the suffix “-iella,” which is a diminutive, perhaps indicating a minor characteristic or a smaller species compared to other related genera, but primarily a tribute to Oudeman. Although the exact details of the choice of this specific name “iella” are not immediately apparent in common sources, suggesting a personal connection or a classification that indicated a more delicate variant.
The specific epithet mucida derives from the Latin “mucidus,” meaning snotty, due to its appearance completely covered in mucilage.

Geographic Distribution and Habitat –
Oudemansiella mucida is a saprophytic fungus that grows, either clump-like or solitary, almost exclusively on dead beech (Fagus) wood. Although it has a strong connection with beech, it has also been found growing on oak on rare occasions. When found on beech trees, it usually outcompetes other fungi locally thanks to a powerful antifungal agent called strobilurin.
It is native to Europe, growing in central and northern Europe and northern Asia. It is found in woodland habitats, especially beech forests, growing on fallen trunks and branches. It is recognizable by its slimy, grayish-white cap.
It grows in autumn and winter.

Recognition –
Oudemansiella mucida is one of the most elegant and ornamental wood-growing fungi in the European mycoflora. When it fruits on the lower surface of tree trunks, the stipe tends to curve, keeping the cap horizontal, with the gills facing downward.
The cap generally measures 2–8 cm in diameter; initially hemispherical or strongly convex, then flattened and convex to almost flat. The margin is thin, sometimes slightly grooved.
The cuticle is highly viscous and mucilaginous, translucent, and porcelain-like in appearance; its color varies from pearly white to light gray, with a darker central disc, often ochre or olive-gray. Microscopically, the cuticle is hymeniform, composed of erect, club-shaped cells without functional basidia.
The hymenium has broad, spaced gills, adnate or slightly decurrent, with a small tooth, sometimes sinuous, interspersed with numerous lamellule. They are white or concolorous to the cap and often slightly mucilaginous.
The stipe is slender, cylindrical or slightly thickened at the base, often sinuous or flexible, 3–10 cm tall and 2–10 mm wide. It is full, rigid, and hard; dry and striated above the annulus, sticky and sometimes finely scaly beneath. The color is white or grayish, darker toward the base, which can darken when handled. In lignicolous fruit bodies, the base is slightly enlarged, sometimes with mycelial rhizomorphs.
The annulus is present, thin but rather broad, membranous and glutinous, white or concolorous to the stipe on the upper part, darker beneath.
The flesh is thin and exiguous, tender and elastic in the cap, fibrous in the stipe, and white in color. The odor is faint, sometimes slightly herbaceous; the flavor is mild and unremarkable.
Under the microscope, white spores are visible en masse, spherical or subglobose, smooth, thick-walled, and guttulate, 15–18 × 13–17 µm, Q ≈ 1.08.
The basidia are clavate, tetrasporic, with clamp-like joints, 76–88 × 16–17 µm.
The cystidia are rare, cylindrical, fusiform, or ventricose, with thin walls, up to 100 × 30 µm.
Thanks to its unmistakable appearance—a slimy, translucent cap, pale color, and typical beech growth—Oudemansiella mucida is rarely confused with other species.

Cultivation –
There are no known cultivation records for Oudemansiella mucida.

Uses and Traditions –
Oudemansiella mucida is a mushroom with an unmistakable appearance, characterized by a shiny white color and a very slimy surface. It typically grows in clusters on decaying beech wood, with which it forms a very close bond, causing wood rot. It is a seasonal species, visible from late summer to late autumn; on windy days, it is not uncommon to witness a curious phenomenon: small fruit bodies detach from the highest branches and “glide” downward, blown by the wind.
Taxonomically, this mushroom is known in Anglo-Saxon countries by several common names, including Porcelain Mushroom, Poached Egg Fungus, and Beech Tuft. These names refer to its delicate, white, slimy appearance, reminiscent of porcelain or egg white. The species was first described in 1794 by Heinrich Adolf Schrader, who named it Agaricus mucidus. Its current scientific name dates back to 1909, when Austrian mycologist Franz Xaver Rudolf von Höhnel placed it in the genus Oudemansiella. This genus, established in 1881 by Carlos Luigi Spegazzini, is named after Dutch mycologist Cornelius Anton Jan Abraham Oudemans (1825–1906). The specific epithet mucida refers directly to the layer of transparent mucus that covers the mushroom’s cap.
From a chemical and biological standpoint, O. mucida is generally considered not toxic. Opinions regarding its edibility, however, differ: some sources consider it slightly toxic, others consider it edible after careful cleaning to remove the mucus, while some even describe it as a good culinary mushroom, supporting these claims with specific recipes. Despite this, in practical mycology it is usually considered to have no nutritional value.
Of great interest, however, is its biological activity: Oudemansiella mucida produces and releases powerful fungicidal substances, known as strobilurins, which allow it to deter or eliminate competing fungi. These compounds have had a significant impact on agriculture, as they have been the basis for the development of fungicides effective against numerous Ascomycetes. The first strobilurins were in fact isolated from wood-bearing fungi such as O. mucida and Strobilurus tenacellus, another white-spored species responsible for wood rot.
The genus Oudemansiella comprises generally glutinous and sticky species, with a more or less slender stem and a membranous ring. In particular, O. mucida is considered a true “lighthouse species”: one of those rare mycological entities with virtually no similar species with which it could be confused. Its almost exclusive growth on dead beech trees, elegant silhouette, white color with a slightly ochre center of the cap, the marked stickiness of the fruiting body, and the almost gelatinous consistency of the flesh make this species extremely easy to recognize in the field, even for the least experienced mycologist.

Preparation Instructions –
Oudemansiella mucida is considered edible, or according to some sources, slightly toxic; however, since it has no culinary value due to its stickiness and the scarcity of pulp once the cuticle is removed, harvesting it is not recommended.

Guido Bissanti

Sources
– Wikipedia, the free encyclopedia.
– GBIF, the Global Biodiversity Information Facility.
– Cetto B., 2008. Mushrooms from the True, Saturnia, Trento.
– Pignatti S., 1982. Flora of Italy, Edagricole, Bologna.
– Conti F., Abbate G., Alessandrini A., Blasi C. (eds.), 2005. An Annotated Checklist of the Italian Vascular Flora, Palombi Editore.

Photo Source:
– https://inaturalist-open-data.s3.amazonaws.com/photos/566467923/original.jpg

Warning: The pharmaceutical applications and dietary uses are provided for informational purposes only and do not in any way constitute medical prescriptions. We therefore decline any responsibility for their use for curative, aesthetic, or nutritional purposes.