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Hygrocybe flavifolia (A.H. Sm. & Hesler) Singer

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Scientific name
Hygrocybe flavifolia
(A.H. Sm. & Hesler) Singer
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
IUCN Red List Criteria
Vellinga, E.
Mueller, G.M.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/75115087/97167815


A rare wax cap species only occurring in mature coastal forests of California (USA), and fruiting very irregularly. It is exemplary for the specific Coast Redwood (Sequoia sempervirens) forest mycoflora that consists of many Hygrocybe and Entoloma subg. Leptonia species.

Assessed as Endangered (EN) under criterion C2a(i) as the number of estimated localities is definitely not more than 125 and population estimate much below 2,500 mature individuals together, no subpopulation has more than 200 mature individuals, and with ongoing habitat loss due to forest harvesting for timber.

Geographic range

Endemic to the United States in coastal northern California, recorded from Orrick in the north to Santa Cruz as the most southern occurrence.

Population and Trends

Since the collection of the type collection at the end of November 1937 in Northern California (Humboldt County), it took till 1994 for a second collection (in Marin County) , after that, another 16 years for reports of this species from several counties (Marin, Santa Cruz, Contra Costa). In the last few years, it has repeatedly been recorded, all from central coastal California.

Population Trend: decreasing

Habitat and Ecology

Terrestrial in Coast Redwood forest (Sequoia sempervirens), and occasionally under Bay Laurel (Umbellularia californica) on bare soil. Nutritional mode not known.


The Coast Redwood, Sequoia sempervirens, occurs from southernmost coastal Oregon southwards to Big Sur in California. These trees depend on summer fogs and winter rains. Due to climate change, the fog patterns have considerably changed during the last 100 years with a significant decrease of the extent of the fog in summer (Johnstone and Dawson 2010), and winter rains have been coming much less reliably during the last 10 years than before.

Coast Redwood forests have been extensively logged for timber and logging is ongoing, resulting in patchiness of available habitat. Today, only 5 % of  the original old growth Sequoia sempervirens forests remains along a 450 mile costal strip in California. Most coast redwood is now young (http://www.savetheredwoods.org/redwoods/coast-redwoods/) Furthermore, in the northern part of the range, the forest understorey vegetation has changed during the last 30 years, with an increase of Polystichum, and a decrease of more open forest floor, resulting in the disappearance of many characteristic fungal species. Habitat destruction is also a threat; one of the known sites of this species is on the campus of the University of California at Santa Cruz.

Conservation Actions

Protect the habitat, in other words, no logging in Coastal Redwood forests. Curb carbon emissions, and reverse the warming trend of global climate.

Use and Trade

Like other waxcaps is edible.

Source and Citation

Vellinga, E. 2015. Hygrocybe flavifolia. The IUCN Red List of Threatened Species 2015: e.T75115087A97167815. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T75115087A75115191.en .Accessed on 5 February 2024

Country occurrence