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Lepiota luteophylla Sundb.

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Scientific name
Lepiota luteophylla
Author
Sundb.
Common names
Yellow-gilled Lepiota
IUCN Specialist Group
Mushroom, Bracket and Puffball
Kingdom
Fungi
Phylum
Basidiomycota
Class
Agaricomycetes
Order
Agaricales
Family
Agaricaceae
Assessment status
Published
Assessment date
2016-04-26
IUCN Red List Category
CR
IUCN Red List Criteria
D
Assessors
Schwarz, C. & Vellinga, E.C.
Reviewers
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/95384528/95385509

Justification

The saprotrophic litter dwelling fungus  Lepiota luteophylla appear to be a very rare fungus with specific habitat requirement. Despite its distinctive appearance and the extensive targeted surveys in appropriate habitat (including type locality) by mycologists, it is only known from a single site, one of the few remaining large-scale groves of Monterey Cypress (Cupressus macrocarpa) that have a well-developed duff layer.

The only site known probably represents a single mycelium likely representing one genet. There are less than five other sites with suitable habitat, and thus, the total population of mature individuals is estimated to be significantly less than 50. This species qualifies for listing as Critically Endangered (CR) under criterion D. Additionally, the lack of encounters despite targeted surveys in the 40 years since its description, and the lack of large groves of cypress in the same age class as the habitat from which it was described leads us to further suggest that it may be Critically Endangered and Possibly Extinct (CR (PE)).

Two upper midwest (USA) collections are considered to be misidentifications and were not considered in this assessment.

Taxonomic notes

Readily distinguished from other Lepiota by its yellow lamellae in combination with its distinctive hymenidermal pileipellis giving rise to loose elements (Vellinga 2010, Siegel and Schwarz 2016).

Accommodation in Cystolepiota is not supported as per Vellinga (2003): “Lepiota scaberula, L. cystophoroides, and L. luteophylla do not have a simple hymenidermal pileus covering, but one giving rise to loose cells. On account of this architecture of the pileus covering, L. luteophylla was accommodated in Cystolepiota (Knudsen 1978). That position does not seem acceptable, in light of the present data. As in many other species of this clade, the spores are not dextrinoid.”

No color images exist of Lepiota luteophylla, and it is represented by very few (if any) collections in the decades since its description.


Geographic range

Lepiota luteophylla apparently has a small and restricted distribution in California, USA. Described and known only from a small area around type collection in duff of Monterey Cypress (Cupressus macrocarpa) at the San Francisco Watershed, San Mateo County, California, USA. Due to its characteristic yellow lamellae, it is unlikely to have been overlooked if encountered by mycologists and thus it is considered to be very rare.

Two collections referred to this name from Michigan and Wisconsin are reported but likely represent a different taxon. One of these has a DNA sequence, but the type specimens have not been sequenced. Critical re-examination is needed before an appropriate assessment can be made.

Population and Trends

It is not possible at present to estimate the population size. But it is obviously a very rare fungus with specific habitat requirement. No collections are known from recent decades since its description in 1971 (Sundberg). Despite intensive surveys specifically aimed at inventorying Lepiota and Leucoagaricus taxa associated with Monterey Cypress at the type locality during 2002 and 2003, this species was not encountered (E. Vellinga pers. comm. 2016). Broader surveys of Monterey Cypress in central California from 2010-2016 (N. Siegel and C. Schwarz pers. comm.) also did not encounter this species. It is unlikely that it is being overlooked, as many smaller and less-conspicuous taxa are regularly recorded by such communities of enthusiasts. Sundberg (1971) describes the seven collections near the type locality as having been encountered annually over a period of six years, probably indicative of a single, perennial mycelium. With only one location and one mycelium known, it is not possible to state anything about population trends.

Population Trend: unknown


Habitat and Ecology

Lepiota luteophylla is a saprobic humus-decayer growing on duff of Monterey Cypress, Cupressus macrocarpa. Like many of California’s coastal Lepiota, Leucoagaricus, and Agaricus, this species probably prefers thick accumulations of needle duff and rich humus of Monterey Cypress. Many such fungi appear to have very strong habitat preferences, and many of them are rarely encountered in other habitats. 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 widely planted globally, the trimmed hedges, windrows, and singletons that are commonly encountered 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 were 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. Fruiting events are likely annual but somewhat opportunistic, like many duff-decaying species found under Monterey Cypress, with potential to occur at any point during the six month wet season.

The habitat of the Wisconsin and Michigan collections were not considered in this account. Given the distinctiveness of the habitat at the type locality, the tendency of Californian Agaricaceae associated with Monterey Cypress to show strong habitat preference, and the distance of the Midwestern records from the type locality, the identification of those few Midwestern collections referred to this species seems suspect.

Threats

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 due to its small native range. The relict populations in Monterey County, California, are two very small groves with a total estimated area of occupancy (AOO) of 13 sq. km. or less.

The type locality for Lepiota luteophylla is a planted grove of significantly large extent, but only a few other similar localities exist in California, none of which have yet yielded records of this fungus.

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 known population in California of Lepiota luteophylla appears to be Critically Endangered and even possibly regionally extinct. There have been no collections in 40 years despite targeted surveys in the type locality and most marginally similar habitats. As of 2016, there is no comparable Monterey Cypress habitat, in terms of a combination of humus development and age of trees, in California.

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 Monterey Cypress mycoflora should be protected.  Recommend 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).

ITS data exists in Genbank for one of the Michigan collections (AY176475); genetic data from a collection from the type locality collection should be obtained and compared. In the unlikely event that the two are found to be conspecific, we would recommend reassessment to Data Deficient, since the habitat association and range would then be very difficult to characterize, but no collections have been made in either location since.


Source and Citation

Schwarz, C. & Vellinga, E.C. 2017. Lepiota luteophylla. The IUCN Red List of Threatened Species 2017: e.T95384528A95385509. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T95384528A95385509.en .Downloaded on 31 January 2021

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