**Amanita griseorosea**
**Definition**
*Amanita griseorosea* is a species of mushroom in the genus *Amanita*, known for its distinctive grayish-pink cap and its occurrence in subtropical regions. It is a member of the *Amanita* section *Phalloideae*, which includes several toxic species.
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# Amanita griseorosea
## Introduction
*Amanita griseorosea* is a basidiomycete fungus belonging to the genus *Amanita*, a group well-known for containing some of the most toxic and deadly mushrooms worldwide. This species was first described in the early 21st century and is primarily found in subtropical forests of East Asia. Like many *Amanita* species, *A. griseorosea* forms ectomycorrhizal relationships with trees, playing an important ecological role in forest ecosystems. Its morphological characteristics, habitat preferences, and toxicological profile distinguish it from closely related species.
## Taxonomy and Nomenclature
### Classification
– Kingdom: Fungi
– Division: Basidiomycota
– Class: Agaricomycetes
– Order: Agaricales
– Family: Amanitaceae
– Genus: *Amanita*
– Species: *Amanita griseorosea*
The species was formally described and named based on its unique morphological features and genetic analysis that differentiated it from other members of the *Amanita* genus. The specific epithet „griseorosea” refers to the grayish-pink coloration of the mushroom’s cap.
### Related Species
*Amanita griseorosea* is closely related to other species in the *Amanita* section *Phalloideae*, which includes notorious species such as *Amanita phalloides* (death cap) and *Amanita virosa* (destroying angel). These species share similar toxic compounds and ecological niches but differ in macroscopic and microscopic features.
## Morphology
### Cap
The cap of *Amanita griseorosea* typically measures between 5 to 12 centimeters in diameter. It exhibits a grayish-pink to pale rose coloration, often with a slightly darker center. The surface is smooth to slightly sticky when moist and may have remnants of the universal veil in the form of warts or patches. The margin of the cap is usually striate (grooved) and may be slightly incurved in young specimens.
### Gills
The gills are free from the stipe and densely packed. They are white to pale cream in color and do not change significantly with age. The edges of the gills are smooth, and the lamellae produce white spores.
### Stipe (Stem)
The stipe is cylindrical, measuring 8 to 15 centimeters in length and 1 to 2 centimeters in thickness. It is white to pale grayish-pink, sometimes with a slightly bulbous base. The surface is smooth or finely fibrillose. A prominent, membranous annulus (ring) is present on the upper part of the stipe, a remnant of the partial veil.
### Volva
At the base of the stipe, *Amanita griseorosea* has a distinct volva, which is a cup-like structure formed from the universal veil. The volva is white and may be somewhat sac-like or lobed.
### Spores
Spores are broadly ellipsoid to subglobose, smooth, and amyloid (staining blue-black in Melzer’s reagent). Spore size typically ranges from 8 to 12 micrometers in length and 6 to 9 micrometers in width.
## Distribution and Habitat
### Geographic Range
*Amanita griseorosea* is primarily found in subtropical regions of East Asia, including parts of China, Taiwan, and Japan. Its distribution is relatively limited compared to more widespread *Amanita* species.
### Habitat
This species grows in mixed forests, often in association with broadleaf trees such as oaks (*Quercus* spp.) and chestnuts (*Castanea* spp.). It forms ectomycorrhizal relationships with these trees, exchanging nutrients and contributing to forest health. Fruiting bodies typically appear in late summer to early autumn, following periods of rainfall.
## Ecology
### Mycorrhizal Associations
As an ectomycorrhizal fungus, *Amanita griseorosea* forms symbiotic relationships with the roots of certain tree species. This mutualistic interaction enhances nutrient uptake for the host tree, particularly phosphorus and nitrogen, while the fungus receives carbohydrates produced by the tree through photosynthesis.
### Role in Ecosystem
By participating in nutrient cycling and soil formation, *Amanita griseorosea* contributes to forest ecosystem stability. Its fruiting bodies also serve as a food source for various forest animals, although its toxicity limits consumption by many species.
## Toxicity
### Chemical Composition
Like other members of the *Amanita* section *Phalloideae*, *Amanita griseorosea* contains potent amatoxins and phallotoxins. These cyclic peptides inhibit RNA polymerase II, leading to severe liver and kidney damage upon ingestion.
### Toxic Effects
Consumption of *Amanita griseorosea* can result in symptoms similar to those caused by *Amanita phalloides* poisoning, including nausea, vomiting, diarrhea, abdominal pain, and, in severe cases, liver failure and death. There is no known antidote, and treatment is primarily supportive and symptomatic.
### Medical Significance
Due to its toxicity, *Amanita griseorosea* is considered a dangerous mushroom and should never be consumed. Awareness and education about this species are important in regions where it occurs to prevent accidental poisoning.
## Identification and Differentiation
### Similar Species
– *Amanita phalloides*: Typically has a greenish cap rather than grayish-pink.
– *Amanita virosa*: Usually all white and lacks the pinkish hues.
– *Amanita roseotincta*: Has a more distinctly pink cap but differs in spore size and volva structure.
### Key Identification Features
– Grayish-pink cap with smooth to slightly sticky surface.
– White, free gills.
– Prominent membranous annulus on the stipe.
– White sac-like volva at the base.
– Amyloid spores measuring 8–12 × 6–9 µm.
## Cultivation and Uses
### Cultivation
There are no known commercial cultivation efforts for *Amanita griseorosea*, primarily due to its toxicity and ecological specificity. Like many ectomycorrhizal fungi, it is difficult to cultivate outside of its natural habitat because of its dependence on symbiotic tree partners.
### Uses
This species has no known culinary or medicinal uses due to its poisonous nature. It is primarily of interest to mycologists and ecologists studying fungal biodiversity and forest ecology.
## Conservation Status
Currently, there is limited information on the conservation status of *Amanita griseorosea*. Its habitat in subtropical forests is subject to pressures from deforestation and land-use changes, which could impact its populations. Further studies are needed to assess its abundance and potential threats.
## Research and Studies
### Phylogenetics
Molecular studies using DNA sequencing have helped clarify the phylogenetic position of *Amanita griseorosea* within the *Amanita* genus. These analyses support its classification in the *Phalloideae* section and help distinguish it from morphologically similar species.
### Toxicology
Research into the toxin profile of *Amanita griseorosea* has confirmed the presence of amatoxins, contributing to the broader understanding of *Amanita* toxicity and mechanisms of poisoning.
### Ecology
Ongoing ecological studies focus on the species’ role in forest nutrient cycles and its interactions with host trees, which may have implications for forest management and conservation.
## Summary
*Amanita griseorosea* is a toxic mushroom species native to subtropical East Asia, notable for its grayish-pink cap and membership in the deadly *Amanita* section *Phalloideae*. It plays an important ecological role as an ectomycorrhizal fungus but poses significant risks to human health due to its potent toxins. Identification relies on a combination of macroscopic and microscopic features, and awareness of this species is crucial in regions where it occurs.
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**Meta Description:**
*Amanita griseorosea* is a toxic mushroom species from East Asia, recognized for its grayish-pink cap and deadly amatoxins. It forms symbiotic relationships with trees and plays a vital ecological role in subtropical forests.