The parasol mushroom, Macrolepiota procera[i], is a favorite edible species in the British Isles and in Europe, due to its excellent taste, large size (some caps are a foot across at maturity), and the fact that this species has few European look-alikes. The picture is a little different in North America, where the species not only has multiple look-alikes (including some that also have “parasol” in their names), some of them toxic, but also a major identity problem. Simply put, what is normally identified as North American M. procera may actually be a group of as-yet unidentified species[ii]. Whether M. procera actually exists in North America among its look-alikes is unclear. At least most of the North American parasols appear to be edible.
The fungus that gives rise to these mushrooms lives underground where it eats dead organic matter. It often grows in open, grassy areas, and seems to generally favor poor soil. It is found more often near some tree species than others, but whether it has any direct connection with the trees (as opposed to simply favoring the same habitat) is unclear.
The parasol’s claim to fame is its edibility; it is delicious, and the large size lends itself to creative uses (reportedly a single cap makes a good pizza crust). However, there is some evidence to support its use as a possible source of anti-cancer drugs.
Parasol Mushroom Identification and Description
Cap: Tan or whitish with light brown scales. Very round initially, opening to almost flat with a bump in the center, sometimes quite large. The flesh is soft and whitish and does not bruise.
Gills: Free from the stem, crowded, white.
Stem: Tall, thin, and scaly, with a ring of tissue that is not attached to the stem but can slide freely up and down it.
Scent: Like maple syrup (though not in all cases).
Taste: Like maple syrup.
Spores: Ellipsoidal, smooth.
Spore color: White
Edibility: Choice, with caution.
Habitat: Grows in pastures, woods, or woodland edges, often in disturbed or poor soil.
Because of the taxonomic uncertainty regarding North American parasols, it is difficult to say anything definite about the mushroom; some of the unidentified look-alikes might be different in important but so far unnoticed ways. An experienced forager who gets to know parasols in one area might also be surprised to find parasols elsewhere that seem quite different—because they are different, being of a different species.
Parasol Mushroom Benefits
The most definite benefit of eating parasol mushrooms is nutritional. Mushrooms in general are high in protein (though mushrooms are rarely eaten in sufficient quantity to be a major protein source) and low in fat and carbohydrates. Parasol mushrooms specifically tend to collect and concentrate certain minerals from the soil, so they can be very high in essential minerals such as iron, calcium, potassium, and zinc[iii] (but see note under “Dangers and Warnings”).
At least one in vitro study showed an extract of parasol mushroom to be effective again certain cancer cells[iv]. Another study found an extract of the parasol to be effective against several other cancer cell lines as well as having moderate antioxidant and antimicrobial activity (standard antibiotics are stronger)[v]. However, the mushroom appears not to have been tested for medicinal value in living subjects yet; in fact, the authors of the second study cannot rule out the possibility that it was the mushroom’s high cadmium content that killed both the microbes and the cancer cells, in which case it could not be used as a safe treatment for anything.
The mushroom has potential, but it is too soon to speculate as to whether it really has medicinal value.
Parasol Mushroom Dosage
Because parasol mushroom are not currently being used as medicine, nor are extracts or products made from the mushroom being sold as medicine, “dosage” really isn’t a consideration. The mushroom is generally considered safe as food, but should not be eaten in excess because of the mushroom’s ability to concentrate minerals, some of which could pose a health risk[vi].
Parasol Mushroom Side Effects and Toxicity
Macrolepiota procera itself is not considered toxic, though it’s always possible for individuals to have hypersensitivities or allergies (the same warning applies to any and all foods). It’s usually best to start slow with new foodstuffs, rather than to discover an allergy only after eating a huge serving. Some writers insist that the parasol can even be eaten raw, though other writers insist it is toxic unless cooked. Since most mushrooms are much healthier to eat after cooking, it is best to err on the side of cooking.
Note: the mushroom can become toxic if it absorbs too much of certain minerals, such as cadmium or mercury. While it might seem obvious not to harvest these mushrooms at all from areas with high levels levels of toxic minerals in the soil, the fungus’ ability to concentrate minerals means the issue is still a concern even if the soil has relatively little of the minerals[vii]. Parasols are still generally considered edible, but it may be best not to eat them to excess. Some authorities suggest not eating them at all.
Another risk, especially in North America, is that of confusing the parasol for one of its look-alikes. Some of these (notably the shaggy parasol) are borderline edible—that is, some people eat them without difficulty while many others get sick—and others are dangerously toxic. A young parasol could even be mistaken for an Amanita, most of which are extremely dangerous. An experienced forager should not have difficulty differentiating the parasol from its known look-alikes, but a newcomer to the hobby might be thrown.
The wildcard is the possibility of unidentified species masquerading as M. procera in North America. Since we don’t know how many of them there might be or which have been extensively eaten, there is no way to be sure that they are all safe to eat.
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[i] Parasol Mushroom (Macrolepiota procera). Mushroom-Collecting.com website, accessed December 19, 2019.
[ii] Kuo, M. (2015). Macrolepiota procera. MushroomExpert. Com website, accessed on December 19, 2019.
[iii] Kuldo, E., Jarzyńska, G., Gucia, M., Falandysz, J. (2014). Mineral Constituents of Edible Parasol Mushroom, Macrolepiota procera (Scop. Ex Fr.) Sing and Soils Beneath Its Fruiting Bodies Collected from a Rural Forest Area. Chemical Papers. 68(4): 484–492.
[iv] Secme, M., Kaygusuz, Eroglu, C., Dodurga, Y., Colak, O. F., Atmaca, P. (2018). Potential Anticancer Activity of the Parasol Mushroom Macrolepiota procera (Agaricomycetes), Against the A549 Human Lung Cancer Cell Line. International Journal of Medicinal Mushrooms. 20(11): 1075–1086.
[v] Kosanić, M., Ranković, B., Rančić, A., Stanojković, T. (2016). Evaluation of Metal Concentration and Antioxidant, Antimicrobial, and Anticancer Potentials of Two Edible Mushrooms Lactarius deliciosus and Macrolepiota procera. Journal of Food and Drug Analysis. 24(3): 477–484.
[vi] Gucia, M., Jarzyńiska, G., Rafal, E., Roszak, M., Kojta, A.K., Osiej, I., Faladysz, J. (2011). Multivariate Analysis of Mineral Constituents of Edible Parasol Mushroom (Macrolepiota procera) and Soils Beneath Fruiting Bodies Collected from Northern Poland. Environmental Science and Pollution Research International. 19(2): 416-431.