It is a highly poisonous fungus. Growing in association with various broadleaved trees, it often appears during summer and autumn, sporting greenish caps with white stems and gills. The toxins it contains, known as amatoxins, are not neutralized by cooking and can be fatal even in small quantities. Just half a mushroom containing enough toxin to kill an adult human, making it responsible for numerous fatal cases of mushroom poisoning throughout history.
Measuring between 5 and 15cm in diameter, the caps of Amanita phalloides start almost white when young, then transition to yellow, bronze, or olive hues, often darker towards the center. They lose all remnants of the universal veil early on, initially appearing egg-shaped before flattening as they mature. The caps, lacking striations at the edges, may crack as they age, emitting a highly unpleasant odor as the mushrooms decay.
The gills are broad, free, and densely packed. Initially, they are pure white, but as the mushroom matures, they gradually turn cream-colored, occasionally with a hint of pink.
The stem typically ranges from 7 to 15 cm in height, appearing off-white with pale zig-zag patterns that are lighter than the color of the cap. These mushrooms often maintain their delicate, hanging ring as they mature. Additionally, they feature a swollen base encased in a large, white, sack-like volva, which may have a greenish tinge internally.
Initially, a thin membrane called a veil covers the gills of the mushroom. As the cap grows, this veil forms a hanging ring around the upper part of the stem, resembling a skirt. The upper side of the ring is white and may have slight ridges, while the underside takes on the color of the cap.
Encircling the expanded basal bulb of the stem, there is a white, membranous, sack-like structure known as the volva, sometimes referred to as the "death cup". However, since the stem's base is frequently buried deep in the soil, the diagnostic cup of the volva may be overlooked if the base breaks off while still in the ground.
While death caps are mycorrhizal fungi, meaning they form symbiotic relationships with tree roots, they have the ability to create arcs and even fairy rings.
The spores of Amanita mushrooms measure 7–12 x 6–9 µm and are typically subglobose to ellipsoid in shape, with smooth, thin walls and a hyaline appearance. When treated with Melzer's iodine reagent, they turn blue, a characteristic feature of the genus. The spore print is white, which is a common trait among Amanita species.
Death cap mushrooms can be found on the ground or in grassy areas, particularly in urban and suburban settings. During mid-summer, they may appear in lawns and grassy strips that are regularly irrigated. These mushrooms often grow near non-native broadleaved trees, particularly those in the birch family such as hornbeams, and also near non-native oak trees. They form ectomycorrhizal associations with their host trees.
The odor of the mushroom starts off mild but turns increasingly sharp and disagreeable as it ages. As for its taste, it is strongly advised not to sample this mushroom. While some individuals who mistakenly consumed death caps described the flavor as excellent, the ensuing consequences of severe poisoning make it an experience no one would willingly repeat.
Under no circumstances should you consume this mushroom. Several toxins, including α-amanitin, found in the death cap, cause severe damage to the liver and kidneys. Freezing or cooking the fungi does not diminish its potency. These toxins, present not only in certain amanitas but also in fungi from other genera like Galerina, Lepiota, and Conocybe, initially lead to gastrointestinal issues, followed by a temporary relief period that can deceive the victim. However, kidney and liver damage progresses rapidly, often leading to coma and death without prompt medical intervention. Even with treatment, recovery is challenging and may require major surgery and a liver transplant.
