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Amanita morrisii Peck

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Scientific name
Amanita morrisii
Common names
Morris' Amanita
Amanite de Morris
Amanite des pinèdes
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Langlois, A.
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/95383179/95385364


Amanita morrisii is a rare ectomycorrhizal fungus in Northeastern North America. It generally grows on wet soil in association with pines, particularly Pinus rigida. Even though it is part of a well studied genus, the species, described 1910, has been found in only 14 sites. Its apparent restriction to the Pine Barrens, which are ecosystems that have been loosing and are expected to lose 10% of its area to development within the next 50 years, indicates that A. morrisii populations will also decline. Its restriction to wetlands within the Pine Barrens makes habitat loss and habitat quality loss critically threatening to A. morrisii, as water quality and water level is expected to be altered.

In total, less than 10,000 mature individuals are estimated to exist: 14 confirmed sites x50 (times more sites because probably often misidentified and most sites are undiscovered ) x2 functional (genetically unique) individuals per site, five mature individuals per functional individual. Together with ongoing decline, this results in an assessment of Vulnerable (VU) C1.

Taxonomic notes

Geographic range

Amanita morrisii is only known from North America. In the United States it is reported from Maine (Cumberland Co.), New Jersey (Burlington Co., Ocean Co.), Massachusetts (Barnstable Co., Essex Co., Middlesex Co.), New Hampshire (Carroll Co.; Overholts 1921), maybe New York (Oneida Co.; uncertain identification of specimen) and is expected in neighboring regions (Tulloss, amanitaceae.org). Its presence is also mentioned in Canada from Quebec province (Laurentides, Monteregie; mycoquebec.org).

USA: One site in Maine (1995), four in Massachusetts (1909, 1910, 1911//1927//1995, 2009//2008 twice), six in New Jersey (1983//1983//1988//1995, 1997, 2008, 2011, 2013//2009//2009, 2012) and one in New Hampshire (prior to 1921). Total 12 sites. There is also one uncertain site (specimen has not been thoroughly examined) in New York (2011, 2012). See amanitaceae.org (Tulloss), Overholts 1921, and mushroomobserver.org.
CANADA: Two sites in Quebec province (1997/unknown year). See mycoquebec.org (2015). Also Y. Lamoureux pers. comm.

Population and Trends

Amanita morrisii is known from only 14 sites across northeastern North America. The species is thought to be declining because of habitat loss due to land development. The Nature Conservancy estimates that if the 1990-2000 rate of loss is maintained, about 10% of the Pine Barrens in northeastern North America (i.e., Northeastern Interior Pine Barrens, North Atlantic Coastal Plain Pitch Pine Lowland and North Atlantic Coastal Plain Pitch Pine Barrens) will be lost to urban development within the next 50 years.

Amanita morrisii is fairly easy to identify due to its characteristic dark brown cap that fades slightly with age and its annulus with a colored underside. However, and even though it is part of a popular group (Amanita), A. morrisii is not a well-known species. Thus, we believe A. morrisii is rarely overlooked but often misidentified when found.

There are 14 sites where A. morrisii has been found and we estimate that there are probably up to 50 times more sites. Each site is thought to represent two functional (genetically unique) individuals. Each functional individual is expected to represent five mature individuals. We estimate the total number of mature individuals of A. morrisii to range between 5,000 and 10,000 (cf. Dahlberg and Mueller 2011).

Population Trend: decreasing

Habitat and Ecology

Amanita morrisii is an ectomycorrhizal fungus species most commonly associating with Pinus rigida, which is most common in the Pine Barrens of northeastern North America. Thus, the fate of A. morrisii is linked to the fate of this habitat. Fungus species associated with Pinus rigida are expected to occasionally associate with other Pinus species (Horton and Bruns 1998), which would explain why A. morrisii was found in Quebec where there is P. sylvestris and P. resinosa but no P. rigida.

Amanita morrisii
fruitbodies are found solitary, in pairs, or gregariously. In Massachusetts, A. morrisii was found in “black vegetable mold” among mosses of swampy area (Natick collections; Tulloss 1991) or in Chamaecyparis thyoides swamp (Barnstable Co., Cape Cod, collection). In New Jersey, it was found in wet sand (poor in organic matter) of Pinus rigida-Quercus barrens, occasionally with Chamaecyparis thyoides nearby, where soil surface is barely above the level of nearby ponds or lakes (Tulloss, amanitaceae.org). In Chamaecyparis thyoides swamps, there are typically Pinus rigida and Betula populifolia present as well (Laidig and Zampella 1999). In New Hampshire, it was found on the ground in damp woods (Overholts 1921). In Quebec province (Canada), A. morrisii was found in Sphagnum under a natural forest of Pinus rigida and Pinus resinosa in an open area. The soil was thin and composed of Sphagnum on bedrock (indicating poor drainage). In Quebec province (Canada), A. morrisii has also been found with ca. 100 years old Pinus sylvestris, P. resinosa and Picea abies on wet moss over thick hummus and sandy soil in a shaded area (Y. Lamoureux pers. comm.).


The main threat to Amanita morrisii is habitat loss and reduction in habitat quality, as the Pine Barrens in northeastern North America are being negatively impacted mostly by development of land (Pinelands Preservation Alliance 2016). Amanita morrisii’s restriction to wetlands within the Pine Barrens makes habitat loss and reduction in habitat quality even more threatening, as water quality and water level is expected to be altered in the Pine Barrens (Pinelands Preservation Alliance 2016). Many historic sites where A. morrisii occurred are in urban areas and are now likely extirpated.

Conservation Actions

Amanita morrisii occurs in at least nine protected sites, either in preserves or parks. Other sites where it occurs should be protected as well.

Amanita morrisii
should be searched for within-range similar habitats to evaluate population size, distribution and population trend. Sites where the species have not been found for a long period of time should be inventoried first to confirm the actual number of extant A. morrisii sites.

Amanita morrisii is a fairly easily identified species due to its cap color and colored partial veil, but it is not well-known by most mycologists. In northeastern North America, where A. morrisii is found, there are numerous groups of amateur mycologists. Members of these groups can be recruited and instructed where to find and how to identify A. morrisii so they can target this species during forays. Data from amateur mycologists can be critical to define A. morrisii population size, distribution and trends.

Source and Citation

Langlois, A. 2017. Amanita morrisii. The IUCN Red List of Threatened Species 2017: e.T95383179A95385364. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T95383179A95385364.en .Accessed on 2 February 2024

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