• Proposed
  • 2Under Assessment
  • 3Preliminary Assessed
  • 4Assessed
  • 5Published

Acroscyphus sphaerophoroides Lév.

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Scientific name
Acroscyphus sphaerophoroides
Common names
Crab Eye Lichen
Mountain Crab-Eye
IUCN Specialist Group
Assessment status
Proposed by
Jessica Allen
Katherine Glew
Katherine Glew
Comments etc.
André Aptroot
Jessica Allen, Curtis Bjork, Karen Dillman, Alan Fryday

Assessment Notes


AOO will likely be small
Likely few individuals

Taxonomic notes

Why suggested for a Global Red List Assessment?

Six locations known from North America: Washington and Alaska in the United State; British Columbia, Canada; Mexico. The distribution is sporadic. Acroscyphus may be limited to the canopy of trees and is only view when dislodged from its substrate.

Geographic range

Acroscyphus sphaerophoroides occurs in disjunct moist high-alpine sites in Asia, North America, South America, and Africa. The species may occur in Mexico, but the one collection from Vera Cruz, Mexico has not been verified. The occurrence in South Africa also has not yet been verified and its recorded latitude and longitude are approximate (South African National Biodiversity Institute).

Population and Trends

In North America the six subpopulations where the species has been observed are comprised of one observed individual.
In China the subpopulation sizes are larger,

six locations in North America

Population Trend: Uncertain

Habitat and Ecology

The Crab Eye lichen occurs in a variety of moist habitats, including Montane Forest with maritime influences, western mesic Forest on Pacific Coast of North America in the Pacific Northwest, alpine tundra, and subalpine tree line.
Habitat for collection from Veracruz Mexico unknown other that near Perote in the highlands of southern Mexico. Collection unverified.
Substrate varies from rock, stumps, bark, and tree canopies. Some data suggest association with nitrified substrates.

Boreal ForestTemperate ForestTundra


Occurrences in forested systems are threatened by logging. Trampling and off-road vehicles are threats to rock-dwelling individuals. Shrub encroachment due to climate change is a threat to tundra subpopulations. Increased fire intensity in forested and tundra systems. Impacts to birds and mammals that lead to reduction of their population sizes could negatively impact the Crabs Eye lichen due to reduced nitrification of substrates.

Unintentional effects: large scale (species being assessed is not the target) [harvest]Recreational activitiesIncrease in fire frequency/intensityHabitat shifting & alteration

Conservation Actions

Some population occur in protected areas.
It is listed as a species of concern in Washington State. In British Columbia it is recognized as S2.
It is recognized as a a species of special concern by COSEWIC.
In China the species is listed as endangered under criteria B1ab(iii)+B2ab(iii).


Site/area protection

Research needed

More extensive searches for currently undocumented populations are needed to better understand the distribution and subpopulation sizes in North America. The species occurrence and subpopulation statuses in Mexico, Patagonia, and South Africa The hypothesized association with nitrified substrates needs to be further investigated.

Population size, distribution & trendsThreats

Use and Trade


Joneson, S., K. Glew.  2003.  Acroscyphus (Caliciaceae) in North America.  The Bryologist.  106(3): 443-446.
Anderson, E.M. 2012. Acroscyphus sphaerophoroides (Caliciaceae) New to Alaska and Most Northerly Report Worldwide. Evansia 29(3), 74-76.
Niu, D.-L.;  Wang, L.-S.; Zhang, Y.-J.; Yang C.-R. 2008. Acroscyphus sphaerophoroides (lichenized Ascomycota, Caliciaceae) in Hengduanshan Mountains.Biochemical Systematics and Ecology. Volume 36, Issues 5–6, May–June 2008, Pages 423-429
COSEWIC 2016: COSEWIC assessment and status report on the Mountain Crab-eye acroscyphus sphaerophoroides in Canada. - Committee on the Status of Endangered Wildlife in Canada, Ottawa. xi, 47 pp.

Country occurrence

Regional Population and Trends

Country Trend Redlisted