The appearance may be frightening at first glance: elongated, pale, solid structures sprouting from the ground or decaying tree trunks and resembling human fingers. This is mushrooms Xylaria polymorphaOne of the most popular types of sex Excelariapopularly nicknamed “Dead Man’s Fingers”.
According to mycologist Cristiano Coelho, professor at the Federal Institute of Piaui (IFPI), the structures are stroma, reproductive bodies that appear on dead wood that gave the fungus its unusual nickname.
In addition to the strange appearance, Coelho highlights that the mushroom is widely used in the splitting process, a technique that involves species capable of forming natural dark lines in hardwood. This species is recorded mainly in Europe, North America and temperate Asia, but representatives of the genus are also found in Brazil.
Environmental paper
the Xylaria polymorpha It grows mainly in moist forests, and is almost always associated with deadwood – fallen logs, stumps, exposed roots, or partially buried wood. Shady environments are conducive to their growth, but they can also appear in parks and gardens where there is decaying wood.
From an ecological point of view, this fungus specializes in decomposing lignin and cellulose, the two main components of wood.
By breaking down these tissues, they release essential nutrients back into the soil. Kelly Cruz, a specialist in Amazonian fungi and a biodiversity doctor in Amazonas, confirms that the fungus “decomposes dead wood and is actively involved in nutrient cycling.”
What is the origin of the strange shape?
The life cycle begins with ascospores, which are microscopic spores secreted by mature stroma. When they encounter moist wood, they germinate and form a mycelium, a network of threads that grow inside the trunk and use its components as an energy source.
When conditions are right—moisture, oxygen, and nutrients—the fungus forms a stroma that appears on the surface. They are hard, dark, elongated structures because they need to be exposed to air to allow spores to be released.
According to Coelho, the shape also protects against water loss and tracks irregularities in the wood, which explains why some warp appears sinuous or branched.
Kelly recalls that mushrooms have two stages in life: an asexual stage, with only the mycelium, and a sexual stage, when the reproductive structures appear well developed.
Despite sex Excelaria It consists mainly of fungi that decompose wood, and some species can appear in soil rich in organic matter, woody fruits, seeds or plant residues accumulated by insects. However, all of them remain specialized in decomposing plant materials, which enhances their ecological role.
Is the species poisonous?
Experts say there is no risk of confusing it with known poisonous mushrooms. The dark, solid stroma has a very distinct appearance from toxic fungi that can cause poisoning. There are no records of accidental poisoning involving… Excelaria. The mushroom is not poisonous, but it is also inedible due to its extremely hard texture and unpleasant taste.
Impact on plantations and living trees
Type Xylaria polymorpha It is an important model for studies related to wood decomposition, as it has a great ability to decompose lignin and cellulose. Their well-defined stroma is useful in research into the classification and development of syndromes.
Its secondary metabolites are sparking interest in biotechnology, and according to Cruz, the mushroom “offers biotechnological potential, antimicrobial activity, and enzymes that can be used in bioremediation.”
This species does not pose a threat to farms or living trees. The fungus only grows on dead wood or wood in an advanced process of decomposition, meaning its presence indicates previous decomposition, rather than an active attack on the plant.
In gardens, it only functions as part of the natural organic matter recycling cycle. Kelly points out that when the fungus appears on trees that are still standing, it happens because the trunk is already infected or compromised.
Strange-looking, and essential to the work of nature: the “Dead Man’s Fingers” mushroom is an example of how decomposition is important in maintaining soil fertility and allowing new forms of life to develop in forests.
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