• Proposed
  • Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Pseudoxenasma verrucisporum K.H. Larss. & Hjortstam

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Scientific name
Pseudoxenasma verrucisporum
K.H. Larss. & Hjortstam
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Under Assessment
Proposed by
Catia Canteiro
Susana P. Cunha, Susana C. Gonçalves
Comments etc.
Catia Canteiro

Assessment Notes


Pseudoxenasma verrucisporum is a resupinate fungi known from Europe, where it grows mainly in humid spruce forests. Total population size is estimated at 111000 mature individuals, with no evidence of population decline so the species is assessed as Least Concern (LC).

Taxonomic notes

P. verrucisporum is the type and only species in the Pseudoxenasma genus, created based on microscopic characteristics (Hjorstam and Larsson 1976). Molecular data has since been used to verify its position as monotypic genus, but the original placement of this species in Russalales was not confirmed and is for now unresolved. (Larsson and Larsson, 2023)

Why suggested for a Global Red List Assessment?

Geographic range

Only known from Northern and Western/Central Europe. Found mostly in the southern regions of Sweeden and Norway (often along the seacoast), but also in Finland, Austria, Belgium and Switzerland. (Kunttu et al., 2021, GBIF.org, 2023) GBIF also includes a soil sample record from Estonia that may indicate a further distribution in this country, but no fruiting bodies have been reported so far.

Population and Trends

P. verrucisporum is known from 37 sites in Europe: Sweeden (22), Norway (7) Austria (5) and Belgium, Finland, and Switzerland. It is an inconspicuous species and likely underecorded, though Kunttu et al. (2021) describe it as overall rare, but locally common. The total number sites, including a multiplier for unrecorded sites, is therefore estimated at 18500. Assuming 3 functional individuals per site (e.g. branches or logs) and 2 mature individuals per functional individual, the population size is estimated at around 111000, following guidelines by Dahlberg and Mueller (2011). There is no evidence of population decline.

Population Trend: Uncertain

Habitat and Ecology

Saprotrophic resupinate fungi. Grows on fallen or still attached dead branches and trunks in closed humid coniferous forests, mainly Picea (e.g. Picea abies) and more rarely on pine (SLU Artdatabanken, 2020). Often found with Globulicium hiemale (Kunttu et al. 2021).

Temperate Forest


No significant threats were identified for this species, and its likely main host (Picea abies) has been assessed as Least Concern (stable population) by the IUCN Red List of Threatened Species (Farjon,2017).

Conservation Actions

P. verrucisporum has been assessed in the National Red Lists of Sweden and Norway as LC. No specific conservation actions are needed for this species.

Research needed

Use and Trade


Country occurrence

Regional Population and Trends

Country Trend Redlisted