Agaricus bernardii
Agaricus bernardii
The salt-loving agaricus or salty mushroom (Agaricus bernardii Quél., 1878) is a mushroom belonging to the Agaricaceae family.
Systematics –
Domain Eukaryota,
Kingdom Fungi,
Division Basidiomycota,
Subdivision Agaricomycotina,
Class Agaricomycetes,
Subclass Agaricomycetidae,
Order Agaricales,
Family Agaricaceae,
Genus Agaricus,
Species A. bernardii
The following terms are synonymous:
– Agaricus algodorus Ingold & Rydb.;
– Agaricus bernardii (Quél.) Sacc.;
– Agaricus campestris subsp. bernardii (Quél.) Konrad & Maubl.;
– Agaricus ingratus (F.H. Møller) Pilát;
– Agaricus maleolens F.H. Møller;
– Fungus bernardii (Quél.) Kuntze;
– Pratella bernardii (Quél.) Quél.;
– Pratella campestris subsp. bernardii (Quél.) L. Corbière;
– Psalliota algodora (Ingold & Rydb.);
– Psalliota bernardii (Quél.) Quél.;
– Psalliota ingrata F.H. Møller.
Etymology –
The currently accepted scientific name is Agaricus bernardii Quél. The genus Agaricus belongs to the Agaricaceae family, in the order Agaricales, and includes numerous species characterized, among other things, by the presence of free gills, initially clear or pink and progressively brown as the spores mature.
The nomenclatural history of the species is slightly more complex than the simple author’s name might suggest. The mushroom was described by Lucien Quélet in the 19th century under the name Psalliota bernardii; the nomenclatural database Index Fungorum lists the original publication as 1878, while other bibliographical sources indicate 1879. Pier Andrea Saccardo subsequently transferred the species to the genus Agaricus, hence the combination commonly used today, Agaricus bernardii.
The specific epithet bernardii is a tribute to G. Bernard, the collector of the collection on which Quélet based his description of the species. The original material came from the area of La Rochelle, an important port on the French Atlantic coast.
Over the course of its taxonomic history, the mushroom has also appeared under other names, including Psalliota bernardii, Pratella bernardii, Fungus bernardii, and Agaricus campestris subsp. bernardii. Modern specialized databases, however, recognize Agaricus bernardii as an accepted species.
The common English name “Salty Mushroom,” or “Salt-loving Mushroom,” describes its most unique ecological characteristic: its ability to thrive in environments with high salt concentrations, which are therefore unfavorable to many other mushrooms. The reference to salt does not necessarily indicate a strong salty flavor, but rather its remarkable halotolerance, that is, the ability to tolerate saline conditions. Recent literature on mushrooms from saline environments, in fact, lists it among the edible species with documented salinity tolerance.
Geographic Distribution and Habitat –
Agaricus bernardii is a species with a very wide distribution and, above all, strongly associated with environments characterized by the presence of salt. It is documented in Europe and other regions of Eurasia, in North America, including Mexico, and in New Zealand; several sources also report its presence in Australia. Available data also shows that the species may have been introduced in some areas, such as Austria and Slovenia, where it is registered as introduced but not considered invasive.
Its original and most characteristic habitat is coastal. The fungus primarily colonizes sandy dune soils, coastal meadows, humid and brackish depressions, the edges of salt marshes, and grassy areas influenced by marine aerosols. It is therefore possible to encounter it in places where the wind continuously transports particles and saline droplets from the sea.
From an ecological standpoint, it is a saprobic species: its nourishment comes from the decomposition of organic matter present in the soil and litter, rather than from the formation of an obligate mycorrhiza with plant roots. The fruiting bodies may appear singly, dispersed, or in clusters, and under certain conditions, they can form characteristic ring-like structures in meadows and pastures.
An interesting peculiarity of its ecology is its ability to exploit non-marine saline environments. In some regions, the species has been observed along verges and roadsides, especially where salts are used during the winter to prevent ice formation. The artificial salinity produced by road salting creates local conditions reminiscent of coastal environments, at least in terms of soil salt concentration. This has favored the species’ expansion inland in some areas.
This apparent adaptability, however, should not be interpreted as a guarantee of the edibility of specimens collected from roadsides. On the contrary, collection in such environments should be avoided due to the possible presence of contaminants from traffic, soil, and road maintenance activities.
Another ecological aspect deserves particular attention. Studies on metal accumulation have shown that A. bernardii can bioaccumulate silver present in contaminated soil. Under certain conditions, particularly high concentrations have been found in fruiting bodies, with higher levels in caps than in stems. This data highlights the importance of considering the quality of the substrate when evaluating the possibility of consuming wild mushrooms: belonging to an edible species does not mean that any specimen, from any environment, is safe to eat.
Identification –
Agaricus bernardii is a robust, compact, and rather squat mushroom, whose general appearance resembles that of some common field mushrooms. The cap generally reaches 5–15 cm in diameter, although dimensions can vary. In young specimens, it is convex and relatively regular, while as it matures, it tends to broaden, becoming largely convex or almost flat. The margin is characteristically highly involuted in young specimens.
The surface of the cap is dry and initially whitish, cream, or ivory; with age, it can take on beige, brownish, or brownish hues. One of the most obvious characteristics of older specimens is the transformation of the surface, which can become fissured, areolate, and covered with small scales or warty growths. This appearance, combined with the brackish habitat, is a useful feature for identification in the field.
The stipe is particularly robust compared to the diameter of the cap. It generally measures about 4–10 cm in length and 2–4 cm in thickness, making it relatively short and thick. It is full, solid, consistent, and generally cylindrical or slightly tapered toward the base. The surface can be smooth or finely wrinkled and, like the cap, can take on a brownish hue with age. It may develop a reddish color when touched or bruised.
The stipe has a thick, membranous white ring, a remnant of the partial veil that protects the gills in young specimens. The ring can take on a rather characteristic shape, enveloping and slightly flaring outward at the top. The structure of the veil has also been one of the factors that have hindered the species’ classification within the Agaricus genus in the past.
The gills are free from the stipe and very close together. In young specimens, they are gray-pink or pale pink; they subsequently become increasingly reddish-brown and finally dark chocolate brown, reflecting the maturation of the spores. This color change is typical of the Agaricus genus and must be distinguished from the color of the flesh, which tends to reddish after cutting or handling.
The flesh is thick, whitish, and firm. A particularly useful characteristic for identification is the tendency to turn pink, orange-red, or brownish-red after being cut or bruised. However, the reaction can be relatively slow and may not always appear immediately intense. A further diagnostic feature is the absence of obvious yellowing of the flesh, including that at the base of the stipe.
The odor, however, is less pleasant. It can be described as brackish, pungent, fishy, or brine-like; the intensity varies from specimen to specimen. It is precisely this olfactory component that explains some of the popular names attributed to the species.
The spore print is dark brown. Under the microscope, the spores are smooth, generally broadly ellipsoidal, relatively thick-walled, and measure around 6–8 × 5–6 μm according to available descriptions. The basidia are predominantly tetrasporic. These microscopic characteristics are especially important when macroscopic identification remains uncertain.
However, identification must be performed with particular caution. The Agaricus genus includes numerous morphologically similar species, and some can be difficult to distinguish simply by visual inspection.
Among the species that can be confused is Agaricus bitorquis, which can have an equally robust appearance. However, A. bitorquis typically has a double ring, lacks the characteristic salty or fishy odor of A. bernardii, generally does not develop the same scaly or warty surface on the cap, and above all, does not display the same obvious reddish reaction of the flesh when cut.
Another comparison can be made with Agaricus benesii, which also has a tendency for its flesh to turn reddish. In this case, however, other characteristics are useful, such as the presence of whitish scales on the lower part of the stem, the absence of the salty odor, and the different ecology, with a greater association with forest and conifer environments.
The taxonomy of A. bernardii has also undergone several infrageneric interpretations. The species has been placed in different sections or subsections of the genus Agaricus, and molecular analyses have helped rule out some previous classifications based solely on morphology. Modern taxonomic databases still recognize it as a distinct and accepted species.
Cultivation –
The cultivation of Agaricus bernardii lacks the tradition, commercial diffusion, or level of standardization achieved by the common cultivated button mushroom, Agaricus bisporus. The species is primarily known as a wild mushroom found in coastal and saline environments, while gastronomic and commercial interest has focused primarily on other species of the Agaricus genus.
Its most interesting physiological characteristic for potential cultivation study is its tolerance to salinity. Unlike many soil-dwelling mushrooms, A. bernardii can fruit in substrates exposed to considerable salt influence and therefore represents one of the most interesting examples of a mushroom adapted to saline environments. A recent review of so-called saline mushrooms classifies it among the edible species with known salinity tolerance.
From a biological standpoint, however, salt tolerance does not mean it is necessary to cultivate the mushroom in a highly saline substrate. Salinity is primarily an ecological characteristic that allows the species to compete in habitats where other fungi are less favored. Any controlled cultivation should therefore simultaneously consider the nature of the substrate, humidity, temperature, aeration, pH, and salt concentration, avoiding the simplistic assumption that greater salt content necessarily results in better growth.
In nature, the species is saprobic and grows in soil, often in sandy substrates rich in organic matter. This distinguishes it from many strictly mycorrhizal edible mushrooms and theoretically makes the study of its cultivation in artificial substrates more accessible. However, large-scale commercial production is currently not comparable to that of A. bisporus.
It is also important not to confuse the species’ tolerance to salinity with its ability to purify contaminated environments. On the contrary, the documented ability to bioaccumulate certain elements, including silver in contaminated soil, constitutes reason for caution. A substrate intended for food production should therefore be rigorously controlled from a chemical and microbiological perspective.
Uses and Traditions –
The primary use of Agaricus bernardii is as a food product. Several mycological sources consider it edible and describe its flesh as palatable, although firmer and tougher than that of the common button mushroom. David Arora compares it to Agaricus bitorquis, emphasizing its slightly tougher texture.
Its gastronomic appeal, however, is strongly influenced by its odor. Some specimens have a relatively mild aroma, while others may give off a characteristic odor of brine, fish, or pungent substances. For this reason, culinary judgments on the species vary: some sources consider it a good edible species, others consider it unappetizing and therefore not particularly interesting to collect.
The English common name Salty Mushroom is probably the most immediate indication of its ecological and sensorial characteristics. Similar names exist in European languages that refer to its growth in salt meadows, dunes, or coastal environments. The GBIF database, for example, collects numerous European vernacular names associated with these very habitats.
However, there is no particularly well-established and specific Mediterranean culinary tradition comparable to that of other wild mushrooms. The species is most prevalent in northern and Atlantic European regions, where dune environments and coastal meadows constitute relatively common habitats and where the mushroom can be observed more regularly.
The fact that it is edible should not, however, lead to indiscriminate collection. Specimens from salted roadsides, industrial areas, landfills, chemically treated land, or other potentially contaminated locations should be left in place. The ability to bioaccumulate elements present in the soil makes the provenance of the material intended for consumption particularly important.
From the perspective of mycological tradition, A. bernardii is primarily interesting as an example of a mushroom specialized in saline environments. Its presence demonstrates how the environmental pressure of salinity, generally unfavorable to many terrestrial organisms, can be exploited by some fungal species as a factor of ecological specialization. Recent scientific attention towards salt-tolerant fungi has in fact considered A. bernardii among the potentially interesting species also in the context of research on so-called “saline mushrooms”.
Preparation Method –
When harvested in a suitable environment and identified with certainty by a competent person, Agaricus bernardii can be prepared in the kitchen similarly to other edible Agaricus mushrooms. The firm flesh is ideal for pan-frying, grilling, or stewing. The flavor may be more pronounced than that of common mushrooms, and the texture may remain meatier and tougher after cooking.
Young, still-firm specimens are generally better suited to cooking than older ones, whose caps tend to crack and develop scales, and whose flesh may become tougher. Before cooking, it’s best to remove any soil and plant debris, gently cleaning the surface without soaking it in water for too long.
A simple preparation method involves slicing the mushrooms and cooking them in a pan with a light sauce, initially allowing the moisture released by the flesh to evaporate, and then cooking them until they reach a soft but still firm consistency. Adding garlic, parsley, extra virgin olive oil, and a small amount of pepper enhances its flavor without completely overpowering its aroma.
The firm flesh is also suitable for grilling, especially when the caps are young and intact. In this case, thorough cooking is preferable, avoiding eating the mushroom raw or semi-raw. As with other wild mushrooms, however, cooking is no substitute for proper species identification and does not guarantee the safety of a specimen collected in a contaminated environment.
A particular consideration is its characteristic salty odor. If the specimen has a strongly unpleasant, abnormal, or ammoniacal odor, or appears deteriorated, old, infested with larvae, or altered, it is prudent not to consume it. Even when a species is considered edible, its edible quality depends on the specimen’s state of preservation, its growth environment, and proper preparation methods.
However, it is not advisable to attempt to “correct” the odor by excessive soaking in salt water or other similar practices. The salty characteristic is part of the mushroom’s physiology and composition and does not necessarily represent a defect that can be eliminated by washing. Furthermore, any provenance from contaminated soil cannot be guaranteed through simple culinary treatments.
Ultimately, Agaricus bernardii can be considered an edible wild mushroom, robust and particularly adapted to saline environments. It is recognizable by its whitish cap that tends to crack and flake with age, its short and very firm stem, its membranous ring, its gills that change from pink to chocolate-brown, its flesh that tends to reddish after cutting, and its characteristic salty odor. Its coastal ecology and remarkable salt tolerance, however, are the most interesting aspects of the species from a naturalistic perspective.
Safety note: The edibility reported for this species does not imply a recommendation for independent harvesting. Agaricus mushrooms can be difficult to distinguish from one another, and identification based solely on a textual description is not sufficient to establish whether a wild mushroom is edible. Furthermore, A. bernardii can grow in environments—roadsides, anthropized land, and contaminated soil—where foraging is particularly inadvisable.
Guido Bissanti
Sources
– Wikipedia, l’enciclopedia libera.
– GBIF, the Global Biodiversity Information Facility.
– Cetto B., 2008. I funghi dal vero, Saturnia, Trento.
– Pignatti S., 1982. Flora d’Italia, Edagricole, Bologna.
– Conti F., Abbate G., Alessandrini A., Blasi C. (a cura di), 2005. An annotated checklist of the Italian vascular flora, Palombi Editore.
Photo source:
– https://svampe.databasen.org/uploads/2022-10290289_Bk5BmIGZo.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.