Species Profile

Frosted Glass-whiskers Atlantic population

Scientific Name: Sclerophora peronella
Other/Previous Names: Frosted Glass-whiskers (Nova Scotia population),Frosted Glass-whiskers Lichen (Nova Scotia population),Frosted Glass-whiskers (Nova Scotia population)
Taxonomy Group: Lichens
Range: Nova Scotia
Last COSEWIC Assessment: November 2014
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern

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Quick Links: | Description | Distribution and Population | Habitat | Biology | Threats | Protection | National Recovery Program | Documents

Image of Frosted Glass-whiskers


Frosted Glass-whiskers is a tiny lichen belonging to a group of lichenized fungi characterized by small, stalked apothecia, the organs that house their reproductive structures and resemble beard stubble. Frosted Glass-whiskers can be recognized by its pale pinkish apothecia, which are raised on fine stalks 0.5 to 0.8 mm tall. Frosted Glass-whiskers is also characterized by tiny, smooth spherical spores, the reproductive structures. The thallus, the leaflike main body of the lichen, is embedded in the substrate, where the fungus is associated with a green alga. Frosted Glass-whiskers is an arboreal lichen, meaning it grows exclusively on trees. It is found on the bark and wood of old trees.


Distribution and Population

Frosted Glass-whiskers is considered very rare throughout its known global range, which includes Europe (Scotland, Germany, Moravia, Denmark, Sweden, Finland, Norway, France, Austria, Italy, and Estonia), the Caucasus in Russia, the United States (western Oregon), and Canada (British Columbia and Nova Scotia). In Canada, this lichen has been collected at only one locality in British Columbia, in 1991, and at two localities in Nova Scotia, in 1998. In British Columbia, the species was reported at the south end of Kitsumkalum Lake. In Nova Scotia, the lichen was observed on Cape Breton Island, in two forests in Inverness County. The entire area of coverage for Frosted Glass-whiskers in the three known Canadian occurrences is probably no more than 1 m2. Despite repeated surveys, the species has been found only once at each locality, and it is estimated that each record represents a single contiguous thallus bearing several apothecia. It is therefore impossible to determine whether these populations are increasing, stable, or declining. However, the two Nova Scotia populations appear healthy.



Frosted Glass-whiskers grows on old deciduous trees, usually on the exposed heartwood of living trunks and more rarely on bark, in humid and rather shaded situations. This arboreal lichen is often associated with old-growth forests in coastal regions, but it is also found in open forests, in clearings, and on the margins of old deciduous forests. In Canada, the single specimen from British Columbia was collected on the bark at the base of a large black cottonwood in a rather shady cottonwood stand. Both of the collections from Nova Scotia were on exposed heartwood of living red maple trees growing in old-growth hardwood stands. Owing to the sensitivity of its green algal partner to frost, this lichen is likely restricted to maritime areas in Canada.



Frosted Glass-whiskers grows exclusively on the wood and bark of older trees and seems to have a preference for forests with stable humidity and small temperature fluctuations. The thallus of Frosted Glass-whiskers is embedded in the substrate. Despite their limited size, all thalli of Frosted Glass-whiskers observed in Canada appear to be healthy, with apothecia containing mature spores. The spores are distributed by wind, rain, and, to a lesser degree, invertebrates. Before a new lichen can grow, the fungal spore must land and germinate in close proximity to a compatible green alga on appropriate substrate. Like all lichens, Frosted Glass-whiskers is a plant organism composed of a fungus and an alga in a symbiotic relationship. This type of mutually beneficial relationship is essential to the survival of the two organisms. Little information is available on the biology of this species. However, it is known that, Frosted Glass-whiskers, unlike other types of lichens, cannot propagate through small organs containing both the alga and the fungus. If it could, these organs, or propagules, would have only to land on a suitable site in order to propagate the species, since both partners would already be present. The lack of vegetative propagules presents an additional challenge for the survival of the species. Finally, like all lichens, Frosted Glass-whiskers is extremely sensitive to air pollution.



The availability of old-growth forests in coastal regions—the preferred habitat of Frosted Glass-whiskers—is unfortunately declining across Canada and throughout most of the world. Habitat destruction from logging of such forests is the primary threat to this lichen. For example, little intact habitat remains in the Acadian Forest Region, within which the species resides in Nova Scotia. Air pollution remains a threat to this lichen in most of the regions in which it occurs. Pollutants threaten both the tree and the lichen growing on the tree.



Federal Protection

More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

In Nova Scotia, the species is protected under the Wilderness Areas Protection Act, which governs specimen collection and habitat destruction in Crown land wilderness areas.

Provincial and Territorial Protection

To know if this species is protected by provincial or territorial laws, consult the provinces' and territories' websites.



PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.

11 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the frosted glass-whiskers Sclerophora peronella in Canada (2005)

    Frosted glass-whiskers (Sclerophora peronella) belongs to a group of lichenized fungi known, colloquially, as calicioid or "stubble" lichens because of their tiny stalked spore-bearing structures. The species has been found on the bark and wood of old trees and can be recognized by the pale colour of its spore-bearing apothecia that are raised on stalks 0.5 to 0.8 mm above the substrate. The main body (thallus) of the lichen is imbedded in the substrate.

COSEWIC Assessments

  • COSEWIC Assessment - Frosted glass-whiskers (2005)

    Frosted glass-whiskers (Nova Scotia population) Designated Special Concern in May 2005. Assessment based on a new status report. ________________________________________________________________ Frosted glass-whiskers (British Columbia population) Species considered in May 2005 and placed in the Data Deficient category. Assessment based on a new status report.
  • COSEWIC status appraisal summary on the Frosted Glass-whiskers Sclerophora peronella in Canada (2015)

    Atlantic population- This tiny stubble lichen is rare over much of its global range; in Canada, thirteen occurrences are in Nova Scotia. The lichen is known only from the exposed heartwood of old red maple trees in wetlands or uplands. The main threat is the loss of habitat and tree removal associated with increased harvesting of upland and ‘low grade’ wetland hardwoods for biomass energy generation, firewood and other products. A second threat is the blow-down of old maple trees by an increasing number of extreme weather events related to climate change. Pacific population- This tiny stubble lichen has only been found at two sites in British Columbia. One in the Skeena River Basin was not found again when the site was revisited. An additional occurrence was recorded subsequently near Albert River, British Columbia, just south of Kootenay National Park. Considerable search effort since has not revealed more sites for this lichen in British Columbia. The exact ecological niche occupied by the Pacific population of this lichen is not understood.

Response Statements

  • Response Statement - Frosted Glass-whiskers , Atlantic population (2015)

    This tiny stubble lichen is rare over much of its global range; in Canada, thirteen occurrences are in Nova Scotia. The lichen is known only from the exposed heartwood of old red maple trees in wetlands or uplands. The main threat is the loss of habitat and tree removal associated with increased harvesting of upland and ‘low grade’ wetland hardwoods for biomass energy generation, firewood and other products. A second threat is the blow-down of old maple trees by an increasing number of extreme weather events related to climate change.
  • Response Statements - Frosted Glass-whiskers (2005)

    This tiny cryptic stubble lichen is very rare or threatened over much of its global range.  Two of the three known locations of this species in Canada are in Nova Scotia. Despite considerable efforts to locate this and other rare calicioid lichens in the province, this lichen is known only from the exposed heartwood of red maple trees in mature/old growth hardwood forest. Threats include potential habitat loss and degradation associated with the decline of old growth forest ecosystems. However, in Nova Scotia each of the two populations appear healthy and are situated within large protected areas on Cape Breton Island.

Management Plans

  • Management Plan for the Frosted Glass-whiskers (Sclerophora peronella), Nova Scotia Population, in Canada (2011)

    The Frosted Glass-whiskers was listed as Special Concern under the Species at Risk Act (SARA) in August 2006. The Minister of the Environment is the competent minister for the recovery of this species and has prepared this management plan as per Section 65 of SARA. This plan was developed in cooperation with the provincial agency responsible for this species and associated habitat (Nova Scotia Natural Resources) as well as Nova Scotia Environment, Mersey Tobeatic Research Institute, and the Boreal Felt Lichen (Atlantic population) Recovery Team.


COSEWIC Annual Reports

  • COSEWIC Annual Report - 2005 (2005)

    2005 Annual Report to the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report - 2014-2015 (2015)

    Under Canada’s Species at Risk Act (SARA), the foremost function of COSEWIC is to "assess the status of each wildlife species considered by COSEWIC to be at risk and, as part of the assessment, identify existing and potential threats to the species". COSEWIC held two Wildlife Species Assessment Meetings in this reporting year (October, 2014 to September, 2015) from November 23 to November 28, 2014 and from April 27 to May 1, 2015. During the current reporting period, COSEWIC assessed the status or reviewed the classification of 56 wildlife species. The wildlife species assessment results for the 2014-2015 reporting period include the following: Extinct: 0 Extirpated: 1 Endangered: 21 Threatened: 11 Special Concern: 21 Data Deficient: 1 Not at Risk: 1 Total: 56 Of the 56 wildlife species examined, COSEWIC reviewed the classification of 40 that had been previously assessed. The review of classification for 24 of those wildlife species resulted in a confirmation of the same risk status as the previous assessment.

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: November 2005 (2005)

    The Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003 as part of its strategy for the protection of wildlife species at risk. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, hereinafter referred to as the 'SARA list'. Canadians are invited to comment on whether all or some of the species included in this document should be added to the SARA list.