Assessment Notes

Justification

Calvatia lloydii is a rarely encountered puffball which grows in the dry coniferous forests of the western North American mountains in habitats strongly threatened by wild fires and drought. Currently, it is known from twelve sites in California, as well as two in Oregon and two in Idaho. Based on data in MyCoPortal and GBIF (both sites queried December 2024) there is only one vouchered specimen and five observations (four from the same site in Oregon) of this species recorded since 1976. The population size is estimated to be very small with a potential range of 240-320 mature individuals, and given the threats to its habitat it is suspected to be in decline. This is a very tentative population size range, and the true value may depend on how many historical sites it still persists in. Further research is required, but a precautionary approach is taken here and C. lloydii is assessed as Endangered under criterion D.

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Taxonomic notes

This species was described from a collection made in Sequoia National Park, California, USA (Zeller 1947). Based on ITS sequences, (Jarvis 2014) it appears that this species belongs in the genus Lycoperdon. Additional gene sequences should be studied to confirm these findings. It was also placed in the genus Handkea by Kreisel (1989).

The species can be tough to distinguish from other species of puffballs; as it can only be recognized by a combination of mostly microscopic characters.

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Geographic range

This species occurs in high elevation forests in the Sierra Nevada and San Bernardino Mountains, with a single site in the Cascade Range in California, USA, two sites in southern Oregon, and reported from two sites in Idaho (Jarvis 2014, MyCoPortal 2024). Most California sites are close to each other in Sequoia National Park.

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Population and Trends

So far, this species is known from a very limited number of high altitude sites: two in Idaho, two in Oregon, and 12 sites scattered in the mountains of California, with five sites in Sequoia National Park, and two in the San Bernardino Mountains (Jarvis 2014, Siegel et al. 2019).

It has been rarely collected (MyCoPortal 2024), with big intervals between collections despite the fact that the high-altitude forests of the mountains are frequently visited by mycologists. Based on data in MyCoPortal and GBIF (both sites queried December 2024) there is only one vouchered specimen and five observations (four from the same site in Oregon) of this species recorded since 1976. A concerted effort to relocate this species at some of the historic sites was attempted in 2016 and 2017, but it wasn’t found during those visits. The species has never been found in the Yuba Pass area even though a mycology class has been held there in the first week of June for the past 30+ years.

With little data and few surveys it is not possible to confidently say if the population is in decline but given threats to the habitat it is suspected to be so. Given that the species is only known from a few reports and has rarely been seen in the pat 30 years, including during dedicated surveys in Sequoia National Park where it was historically most common, its current population size is considered to be very small. Taking into account the known historical sites (16), each of which could be said to contain one functional individual (which equates to two mature individuals per Dahlberg and Mueller 2011), it would have a known historical population size of 32 mature individuals. Historically, the total number of sites may have been 10 times as many as the known number of sites, thus giving a maximum historical population size of 320 mature individuals. Given the very low reporting rate, it is plausible that the population has undergone a reduction (although we cannot say if there is a continuing decline), and so it may now only be present in c. 75% of historical sites. This would give a minimum population size estimate of 240 mature individuals.

Population Trend: Decreasing

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Habitat and Ecology

This species is saprotrophic (living from dead plant material), growing in duff in high altitude dry conifer forests, 5,000-8,000 ft asl, with Abies, and Pinus ponderosa and occasionally Quercus kelloggii. Fruiting occurs from May to October (Zeller 1947; collection data from MyCoPortal 2024), after the snow melt and after summer thunder and rain storms.

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Threats

Habitat destruction because of forest fires is the main threat. As a result of the droughts in California (2012-2015) and changing weather patterns due to climate change, many forest fires have burned in the western states; these fires are more intense, and cover wide areas, due to the practice of forest fire suppression during the last 100+ years.

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Conservation Actions

This species should be added to the US Forest Service Sensitive Species list, and populations manged when discovered. Surveys for this species, especially in the southern Sierra Nevada mountains are needed. Attempts should be made to relocate this species in Sequoia National Park, the area with the largest number of the California collections (including the type) were made in the 1940’s, but has not been collected there since. Further research should also be conducted to try to get a clearer indication of the population trend.

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Use and Trade

No use/trade is known.

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Source and Citation

Mueller, G.M. & Siegel, N. 2025. Calvatia lloydii. The IUCN Red List of Threatened Species 2025: e.T95384407A95385419. Accessed on 25 November 2025.

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• Country occurrence