Various methods can help determine whether mushrooms are safe for consumption. Besides specific defining characteristics and distinct visual differences, another feature to consider is whether they bruise or bleed a specific color. Observing these color changes can be incredibly helpful in identifying the specific type of mushroom and determining whether it is poisonous.
Although an important and helpful feature, color change on its own is considered one of the least reliable ways to identify different mushroom types. The main reason is that there are always variations. Color change can also vary significantly depending on the age of the fungus. Use mushroom bruising and bleeding as additional tools, in combination with other mushroom identification measures.
Mushroom Bruising
Mushroom bruising involves nicking the top and bottom of the mushroom cap and observing any color changes. As specimens that are not fresh don’t give reliable results, it is important to do this within the first 30 minutes of picking the mushroom.
Why exactly does mushroom bruising occur? When certain compounds present in the cell wall of the mushroom are exposed to air, a chemical reaction results in the color change. Cutting into the cap of the mushroom breaks its cell wall, allowing the oxygen in the air to interact with the compounds present in the mushroom and change them. For example, when you nick the cap of Gyroporus cyanescens and break its cell wall, exposing it to the oxygen in the air, the variegatic acid present in the mushroom converts to the blue-colored molecule quinone methide.
Many well-known mushrooms bruise blue. In fact, blue bruising is one of the most famous features of psilocybin-containing mushrooms (aka magic mushrooms). Blue bruising, along with two other features, indicates that a particular mushroom can potentially be an active psilocybin mushroom. However, a common and very important rule for boletes is that you should never consume a mushroom with a red pore surface that bruises blue. Since many blue bruising boletes are poisonous, it is best to avoid them entirely.
A common misconception is that all blue bruising mushrooms are safe to eat or are hallucinogenic. The bolete rule above proves that this is simply not true. This potentially dangerous, or in many cases life-threatening, myth further reiterates why solely identifying mushrooms through bruising is not reliable and a bad idea overall.
Mushroom Bleeding
When you cut into certain mushrooms, they will exude a milky liquid substance. Although the term is mushroom ‘bleeding’, it is not real blood but rather a natural latex generated when the mushroom is cut into or injured.
While the precise reasoning why these mushrooms produce the latex substance is not fully understood, it is believed to be a natural defense mechanism of the mushroom. This is mainly due to its bitter taste and the fact that it instinctively dries to form a protective coating around the injury or cut to prevent bacteria or any other contaminants from entering.
Some of the most popular bleeding mushrooms are in the Lactarius genus. These mushrooms are commonly referred to as the ‘milky caps’ because of the milky latex they exude when injured.
A great example is the blue bruising and bleeding of Lactarius indigo, the indigo milk cap. When this mushroom is cut into, it bleeds a bright blue latex that progressively turns green.
Examples of Bruising and Bleeding Mushrooms
Here are a few examples of bruising and bleeding mushrooms. Note that this list is by no means exhaustive, and there are many more examples.
- Boletus campestris: This mushroom bruises blue or blue-green. Many yellow-pored boletes bruise blue.
- Russula rubescens: This mushroom bruises a reddish color, which then slowly turns to black.
- Agaricus bisporus (white button mushroom): The Agaricus bisporus, commonly known as the white button mushroom, typically bruises a pinkish color. You can stick your finger into a grocery store-bought white button mushroom to test it out.
- Mycena haematopus: This mushroom bleeds a purplish color.
- Psilocybe cubensis: The stems of the Psilocybe cubensis bruise blue or blue-green. This is a hallucinogenic mushroom, but it’s important to note that not all hallucinogenic mushrooms bruise blue.
- Lactarius chrysorrheus: Bleeds a white latex substance that dries to a deeper yellow color.
- Lactarius helvus (maple syrup milky cap): The Lactarius helvus, commonly known as the maple syrup milky cap, bleeds colorless latex that smells like maple syrup.
Next time you are identifying mushrooms, check for bruising and/or bleeding. Although no identification is guaranteed and mushroom bruising and/or bleeding is not considered a reliable identification tool on its own, it can provide you with some important and helpful information in your mushroom identification process.
Important tip: If you are using mushroom bleeding in your mushroom identification process, observe and take note of both the initial liquid color and the final dried color, as these two colors will often be different.
Conclusion
Identifying mushrooms through bruising and bleeding can provide valuable insights into their species and safety. However, use these methods as supplementary tools rather than sole identification techniques. Always combine them with other identification measures to ensure accuracy and safety. When foraging, prioritize your safety by avoiding mushrooms with potentially dangerous characteristics, such as blue bruising and red pore surfaces in boletes.
FAQs
1. Can bruising alone determine if a mushroom is safe to eat?
No, bruising alone is not a reliable method for determining the safety of a mushroom. It should be used in combination with other identification methods.
2. Why do some mushrooms bruise blue?
Blue bruising occurs due to a chemical reaction between the compounds in the mushroom and oxygen when the cell walls are broken.
3. Are all blue bruising mushrooms hallucinogenic?
No, not all blue bruising mushrooms are hallucinogenic. Some blue bruising mushrooms can be poisonous.
4. What is mushroom bleeding?
Mushroom bleeding refers to the exudation of a milky latex substance when a mushroom is cut or injured.
5. Are there any edible mushrooms that bruise or bleed?
Yes, some edible mushrooms can bruise or bleed. For example, Agaricus bisporus (white button mushroom) bruises pink, and Lactarius indigo bleeds blue latex.
