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Lepiota rhodophylla Vellinga

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Scientific name
Lepiota rhodophylla
Author
Vellinga
Common names
 
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Agaricaceae
Assessment status
Assessed
Preliminary Category
CR D
Proposed by
Christian Schwarz
Assessors
Else Vellinga
Editors
Christian Schwarz, Noah Siegel
Contributors
Todd Osmundson
Reviewers
Anders Dahlberg

Assessment Status Notes

The only site known probably represents a single mycelium likely representing 1 genet. The total number of sites with suitable habitat is estimated population to be less than 5 and thus, the total population of mature individuals is estimated to be less than 50.

Therefore this species qualifies for listing as Critically Endangered (CR) within the D criterion.

Taxonomic notes

This species is readily recognizable (as long as the genus is correctly ascertained) by the pink lamellae and stout stature of the fruitbodies (Siegel and Schwarz 2016).


Why suggested for a Global Red List Assessment?

Lepiota rhodophylla is known only from the type locality, a small area at the San Francisco Watershed, California, USA. The type habitat is one of the few remaining large-scale groves of Monterey Cypress (Hesperocyparis macrocarpa) which have a well-developed duff layer.

Planted Monterey Cypress are severely impacted by infection of the fungal disease cypress canker (Seiridium cardinale). This tree (which dominates and defines that habitat at the type location) is listed as Vulnerable (IUCN, 2011) due to its tiny native range (two relict populations in Monterey County, California):

The pink lamellae are diagnostic within the genus, and should draw attention and special notice even when encountered by casual mushroom enthusiasts. A thorough search of mushroom observations generated by citizen-scientists in California did not reveal any candidate observations. It is possible that this species is being overlooked due to confusion with immature Agaricus species. However, this is relatively unlikely given increasing sophistication of taxonomic observers in this area, and that many taxa that are more difficult to identify or less-conspicuous are regularly recorded by such communities of enthusiasts.


Geographic range

This species was described from and is currently known only from a small area in at the San Francisco Watershed, San Mateo County, California, USA (Vellinga 2007).


Population and Trends

Very few large-scale groves of Monterey Cypress-dominated habitat exist. This tree (which dominates and defines that habitat at the type location) is listed as Vulnerable (IUCN 3.1) due to its tiny native range (two relict populations in Monterey County, California): The native range of the tree is represented by two very small groves with a total estimated area of occupancy (AOO) of 13 sq. km. or less.

The naturalized groves of Monterey Cypress are at risk of destruction by fire, drought stress, and other impacts related to climate change.  Plantings of these trees near human settlements are often severely degraded by the removal of lower limbs and duff (making the habitat less suitable for associated litter-inhabiting fungi), as well as by extensive intrusion smothering the duff layer by a number of invasive plants including Hedera helix, Delairea odorata, and Vinca major.

The only known site for Lepiota rhodophylla is unique, in that it is on an East-facing slope, away from the cooler climate of the coast where the other suitable sites are. This makes the habitat more vulnerable to Seiridium cardinale (Cypress Canker. Furthermore, the land management practice at the site is predisposed to removal of this tree. These two factors combined increase the likelihood that the type locality will be degraded. Planted Monterey Cypress are severely impacted by infection of the fungal disease cypress canker (Seridium cardinale) (Graniti 1998).

Population Trend: Uncertain


Habitat and Ecology

Lepiota rhodophylla is a saptrotrophic fungus growing on duff of Monterey Cypress,Hesperocyparis macrocarpa) and like many of California’s Lepiota, Leucoagaricus and Agaricus, it is primarily associated with Monterey Cypress. These fungi appear to have very strong habitat preferences, and many of them are rarely or never encountered in other habitats.

Fruiting events for Lepiota rhodophylla are likely annual, but may be somewhat opportunistic - many duff-decaying species found under Monterey Cypress, with potential to occur at any point in the wet season.

Stands of Monterey Cypress in coastal California are rich in lepiotaceous species, white-spored members of the family Agaricaceae (Vellinga, 2006).  A high number of these species may grow together in a small area, such as a single Monterey cypress stand in the San Francisco Watershed, where 25 species were encountered in the 2002/2003 mushroom season (Vellinga, 2004).

Although Monterey Cypress is very widely planted, the trimmed hedges, windrows, and singletons that are most commonly encountered lack accumulations of duff, and don’t form closed canopies, and thus do not appear to be suitable habitat for many of the rarer fungi that associate with Monterey Cypress where it occurs in larger groves. Of the few older stands of this tree that do exist (most of which are planted), only a few have a well-developed duff layer.  Even among these sites, there appears to be significant heterogeneity in the occurrence of cypress-associated fungi to these refugia, perhaps limited by constraints on dispersal.

Temperate Forest

Threats

Very few large-scale groves of Monterey Cypress-dominated habitat exist. The only known site is away from the cooler climate of the coast, which makes the habitat more vulnerable to Seiridium cardinale (Cypress Canker) - in combination with the land management practice at the site being predisposed to removal of this tree, there is significant likelihood that the type locality will be degraded. Planted Monterey Cypress are severely impacted by infection of the fungal disease cypress canker (Seridium cardinale) (Graniti 1998). This tree (which dominates and defines that habitat at the type location) is listed as Vulnerable (IUCN 2011) due to its tiny native range (two relict populations in Monterey County, California): The native range of the tree is represented by two very small groves with a total estimated area of occupancy (AOO) of 13 sq. km. or less.

The naturalized groves of Monterey Cypress are at risk of destruction by fire, drought stress, and other impacts related to climate change.  Plantings of these trees near human settlements are often severely degraded by the removal of lower limbs and duff (making the habitat less suitable for associated litter-inhabiting fungi), as well as by extensive intrusion smothering the duff layer by a number of invasive plants including Hedera helix, Delairea odorata, and Vinca major.

Fire & fire suppressionNamed speciesProblematic native species/diseasesDroughts

Conservation Actions

Survey existing groves of Monterey Cypress (both in native range as well as in planted groves) to determine whether the known population from the type locality is still extant, and whether other populations exist. Develop interpretive materials for use at state parks, watersheds, state property, and public lands where Monterey Cypress groves exist. Work to develop understanding that existing groves which act as refugia for the Monterey Cypress-associated mycoflora should be protected.

Recommend to land managers in more urban areas that groves of Monterey Cypress be managed in such a way that the duff layer remains as intact as possible (avoid removing lower limbs, avoid raking duff, limit foot traffic). Remove invasive vines and other plants from existing Monterey Cypress groves, especially Common Ivy (Hedera helix), Cape Ivy (Delairea odorata), and Greater Periwinkle (Vinca major).

Site/area protectionInvasive/problematic species controlAwareness & communications

Research needed

Survey existing groves of Monterey Cypress (both in native range as well as in planted groves) to determine whether the known population from the type locality is still extant, and whether other populations exist.

Population size, distribution & trendsPopulation trends

Use and Trade


Bibliography

Vellinga, E.C., 2007 Lepiotaceous fungi in California, U.S.A. – 2. Lepiota rhodophylla. Mycotaxon 98: 205-211.

Vellinga, E.C. (2004). Ecology and distribution of lepiotaceous fungi – a review. Nova Hedwigia 78: 273-299.

Siegel, N and Schwarz, C. 2016. Mushrooms of the Redwood Coast. Ten Speed Press, Emeryville, CA.

Graniti, A. 1998. Cypress canker: A pandemic in progress. Annual Review of Phytopathology. 36:91-114.


Known distribution - countries

Regional Population and Trends

Country Trend Redlisted