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Leucoagaricus hesperius Vellinga

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Scientific name
Leucoagaricus hesperius
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Vellinga, E.C.
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/125433553/125435465


Leucoagaricus hesperius is a robust, medium-sized saprotropic fungus restricted to Monterey Cypress (Cupressus macrocarpa) groves in coastal central California, U.S.A., which are characterized by a thick undisturbed litter layer, an open character and the absence of a herbaceous understory. This habitat this species is known from is becoming increasingly rare. It is known from only two such sites. The number of suitable sites is very small, as disturbance of the litter layer, the dying of the overstory trees, and the presence of invasive grasses and herbs have made other sites unsuitable. Though the species is known only from two subpopulations, and has been much looked for, it might be more widespread; it is not easy to identify in the field. The species is estimated to be presented by fewer than 1000 mature individuals in total and in each subpopulation. It is assessed as Vulnerable based on very small population.

Geographic range

This species is endemic to California, USA. Known from two localities in coastal central California, one in San Mateo County, and one in San Francisco County.

Population and Trends

There are only two subpopulations known for the species, one where the species was only found in 1990; in the other locality it has been found several times. It is not known from other sites. Though the species is known only from these subpopulations and has been much searched for, it might be more widespread as it is not easy to identify in the field. The species is estimated to be represented by fewer than 1000 mature individuals in total and in each subpopulation.

Population Trend: unknown

Habitat and Ecology

Leucoagaricus hesperius is a rather robust, medium-sized species with a pinkish-reddish brown velvety cap and gills that turn red with age. The fruitbodies become green with ammonia. It is saprotrophic in Monterey Cypress (Cupressus macrocarpa) groves that are open, without a herbaceous understory and with an undisturbed thick litter layer. The spores are wind-dispersed.


In general, the major threats to this habitat are: disturbance of the litter layer, invasion of non-native weeds and grasses such as Vinca major, Ehrharta erecta and Hedera helix, and conversion to oak woodland. Monterey Cypress is an endangered (VU) species native to California, which has been planted widely as windbreak in coastal areas (http://dx.doi.org/10.2305/IUCN.UK.2013-1.RLTS.T30375A2793139.en.). The grove in San Mateo County is over 100 years old, and exceptional because of its east-facing slope. It is not open to the public, but disturbance is an issue. The plantation in San Francisco County is very disturbed, and the species has only been collected there once. Disturbance and weed invasions are the main threats.

Conservation Actions

Conservation actions required to protect this species are: raising awareness about the mycological value of Monterey Cypress groves with an undisturbed well-developed litter layer, removal of invasive weeds in suitable habitats, and monitoring of existing sites.

Source and Citation

Vellinga, E.C. 2019. Leucoagaricus hesperius. The IUCN Red List of Threatened Species 2019: e.T125433553A125435465. https://dx.doi.org/10.2305/IUCN.UK.2019-1.RLTS.T125433553A125435465.en .Accessed on 16 February 2024

Country occurrence