Species Profile

Incurved Grizzled Moss

Scientific Name: Ptychomitrium incurvum
Taxonomy Group: Mosses
COSEWIC Range: Ontario
COSEWIC Assessment Date and Status Change: December 2021
COSEWIC Status: Extirpated
COSEWIC Status Criteria:
COSEWIC Reason for Designation: This small moss is widely distributed in the eastern deciduous forests of North America but is rare throughout the northern portion of its range. In Canada, it was only known from one occurrence in southern Ontario, documented in 1825. Despite many years of botanical activity in the region, the species has never been rediscovered.
COSEWIC History of Status Designation: Designated Extirpated in November 2002. Status re-examined and confirmed in May 2012 and December 2021.
SARA Status: Schedule 1, Extirpated
Date of Listing (yyyy-mm-dd): 2005-01-12

Please note that this information is provided for general information purposes only. For the most up to date and accurate list of species listed under the Species at Risk Act, please see the Justice Laws Website.

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Quick Links: | Taxonomy | Description | Habitat | Biology | Reasons for extirpation | Protection | Recovery Initiatives | National Recovery Program | Documents


There does not appear to be any current controversy surrounding the taxonomic status of the Incurved Grizzled Moss. It belongs to the family Ptychomitriaceae and has been known by various scientific names, including Weissia incurva, Brachysteleum hampeanum, B. incurvum, Glyphomitrium incurvum, Grimmia muehlenbergii, G. parvula, and G. hookeri.



The Incurved Grizzled Moss is a small, cushion-forming moss. It grows in 2-to-6-mm-high tufts on rocky surfaces, and varies in colour from yellowish-brown to blackish-green. The leaves are curled when dry, and upright, spreading, and somewhat incurved when moist.


Distribution and Population

The Incurved Grizzled Moss has a temperate global distribution. Some populations are found in the mountainous regions of Europe (Pyrenees, Alps, and Caucasus) but most are centred in the eastern and southeastern United States. A single historical record from 1828 is the only known occurrence of the Incurved Grizzled Moss in Canada. It was collected “near the Falls of Niagara in Upper Canada” (before Ontario was recognized as a province).



The Incurved Grizzled Moss grows in the eastern deciduous forest, on both calcareous (containing calcium carbonate) and non-calcareous rocks. It is commonly found on the surface, and in small crevices, of boulders in open hardwood forests. It is occasionally observed at the base of trees or on logs. Incurved Grizzled Moss also frequently becomes established on man-made structures such as rock walls and gravestones.



Since the Incurved Grizzled Moss does not show a preference for rocks based on their chemistry (calcareous versus non-calcareous), it seems unlikely that nutrition limits its distribution. The Incurved Grizzled Moss has both sperm- and egg-producing organs on the same plant. Self-fertilization is therefore possible, eliminating the need for male and female plants to occur close to each other in order to produce spores and propagate new plants. Vegetative (non-sexual) spread is apparently rare for this moss, and is consistent with its preference for discrete habitats such as rocks and crevices that are interspersed with unfavourable habitat. The moss produces eggs that are incapable of moving independently; water is required for sperm to be able to reach them. The fertilized egg later produces spores that are spread by the wind. When the spores germinate and start to grow, they are sensitive to drying out and require high humidity. The leafy plants produced in the next stage of the moss’s life cycle are more robust, and better able to withstand the lack of protection from the elements and the variable humidity characteristic of rocky habitats.


Reasons for extirpation

It is not known why the Incurved Grizzled Moss became extirpated from Canada. The historical record shows that it was at the extreme northern limit of its range, and species at the edge of their ranges are more vulnerable to chance events. Human activity, resulting in pollution and the loss of habitat, may also have contributed to the extirpation of the species from southern Ontario.



Federal Protection

The Incurved Grizzled Moss is protected under the federal Species at Risk Act (SARA). More information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.

Provincial and Territorial Protection

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


Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for the Incurved Grizzled Moss (Ptychomitrium incurvum) in Canada
Status Final posting on SAR registry


Recovery Progress and Activities

Summary of Progress to Date Recovery of the Incurved Grizzled Moss in Canada is not technically or biologically feasible at this time. Reasons for the extirpation of the Incurved Grizzled Moss are not known, nor are the species’ threats understood, therefore recovery cannot take place. The feasibility of its recovery will be re-evaluated at a minimum of every five years. Summary of Research/Monitoring A reconnaissance survey in 2001 conducted by the Canadian Museum of Nature was unsuccessful in rediscovering the species. Despite many years of collection in the region where it was initially discovered in 1828, no evidence of the species growing in Canada has been found. Summary of Recovery Activities The recovery of this species is considered “not feasible” and will not be pursued until the species is rediscovered in Canada. URLs Ontario’s Biodiversity: Species at Riskhttp://www.rom.on.ca/ontario/risk.php?doc_type=fact&lang=&id=293


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

Response Statements

  • Response Statement - Incurved Grizzled Moss (2013-01-03)

    This small moss is widely distributed in the deciduous forests of eastern North America, with a frequency of occurrence that declines toward the northern portion of its range. In Canada, the only known record for the species is from the Carolinian zone of southern Ontario (Niagara Falls) in 1825. Despite considerable search effort in the region, the species has never been rediscovered.
  • Response Statements - Incurved Grizzled Moss (2004-04-21)

    A response statement is a communications document that identifies how the Minister of the Environment intends to respond to the assessment of a wildlife species by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The document provides a start to the listing and recovery process for those species identified as being at risk, and provides timelines for action to the extent possible.

Recovery Strategies

  • Recovery Strategy for the Incurved Grizzled Moss (Ptychomitrium incurvum) in Canada (2007-11-20)

    Incurved grizzled moss is under the management jurisdiction of the Ontario provincial government. The Species at Risk Act (SARA, Section 37) requires the competent minister to prepare recovery strategies for listed extirpated, endangered or threatened species. Incurved grizzled moss was listed as Extirpated under SARA in June 2003. The Canadian Wildlife Service – Ontario Region, Environment Canada, developed this recovery strategy. The Province of Ontario reviewed and acknowledged receipt of the strategy. The proposed strategy meets SARA requirements in terms of content and process (Sections 39–41).


  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Species at Risk Act (2004-04-21)

    This Order acknowledges receipt by the Governor in Council of the assessments of the status of wildlife species done pursuant to subsection 23(1) of the Species at Risk Act (SARA) by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC). The purpose of SARA is to prevent wildlife species from being extirpated or becoming extinct, to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity and to manage species of special concern to prevent them from becoming endangered or threatened.
  • Order Amending Schedules 1 to 3 to the Species at Risk Act (volume 139, number 2, 2005) (2005-01-12)

    Schedule 1, the List of Wildlife Species at Risk of the Species at Risk Act (SARA), is amended by Order of the Governor in Council (GIC), on the recommendation of the Minister of the Environment, by the addition of 73 species. This Order is based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and follows consultations with provincial and territorial governments, Aboriginal peoples, stakeholders and the public, and analysis of costs and benefits to Canadians.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2003 (2003-10-01)

    May 2003 Annual Report to the Canadian Endangered Species Conservation Council by the Committee on the Status of Endangered Wildlife in Canada.
  • COSEWIC Annual Report - 2011-2012 (2012-10-05)

    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 (September 1, 2011 to September 30, 2012) from November 21 to 25, 2011 and from April 29 to May 4, 2012. On February 3, 2012, an Emergency Assessment Subcommittee of COSEWIC also assessed the status of the Tri-colored Bat (Perimyotis subflavus), the Little Brown Myotis (Myotis lucifugus), and the Northern Myotis (Myotis septentrionalis). During the current reporting period COSEWIC assessed the status or reviewed the classification of 67 wildlife species. For species already found on Schedule 1 of SARA, the classification of 32 species was reviewed by COSEWIC and the status of the wildlife species was confirmed to be in the same category (extirpated - no longer found in the wild in Canada but occurring elsewhere, endangered, threatened or of special concern). The wildlife species assessment results for the 2011-2012 reporting period include the following: Extinct: 1 Extirpated: 4 Endangered: 29 Threatened: 10 Special Concern: 15 Data Deficient: 2 Not at Risk: 6 Total: 67 Of the 67 wildlife species examined, COSEWIC reviewed the classification of 49 species that had been previously assessed. The review of classification for 26 of those species resulted in a confirmation of the same status as the previous assessment (see Table 1a).

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: March 2004 (2004-03-03)

    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.
  • Consultation on Amending the List of Species under the Species at Risk Act: Terrestrial Species – December 2012 (2013-01-03)

    As part of its strategy for protecting wildlife species at risk, the Government of Canada proclaimed the Species at Risk Act (SARA) on June 5, 2003. Attached to the Act is Schedule 1, the list of the species that receive protection under SARA, also called the List of Wildlife Species at Risk. Please submit your comments by March 4, 2013, for terrestrial species undergoing normal consultations and by October 4, 2013, for terrestrial species undergoing extended consultations. Consultation paths.
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