Species Profile

Small-flowered Sand-verbena

Scientific Name: Tripterocalyx micranthus
Other/Previous Names: Sand Verbena,Abronia micrantha
Taxonomy Group: Vascular Plants
COSEWIC Range: Alberta, Saskatchewan
COSEWIC Assessment Date and Status Change: November 2002
COSEWIC Status: Endangered
COSEWIC Status Criteria: B1ab(iii)c(iv)+2ab(iii)c(iv)
COSEWIC Reason for Designation: An annual of a few widely dispersed sand hill habitats where populations occupy very small sites and consist of low numbers that fluctuate greatly with precipitation levels.
COSEWIC History of Status Designation: Designated Threatened in April 1992. Re-examined and designated Endangered in November 2002.
SARA Status: Schedule 1, Endangered
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: | Photo | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents

Image of Small-flowered Sand-verbena

Small-flowered Sand-verbena Photo 1



The Small-flowered Sand-verbena is an annual plant that grows to heights of 20 to 50 cm. It branches near the base and spreads along the ground, with only the tips of the stems turned upwards. The paired leaves are 2 to 6 cm long, 1 to 3 cm wide, and have prominent veins. The tiny, greenish-white flowers are quite striking. They are arranged in dense clusters with a ring of modified leaves underneath, and tend to open in the late afternoon. The fruit are pale pinkish-green, about 2 cm long, and have two to three thin, papery wings.


Distribution and Population

The Small-flowered Sand-verbena is a species of western North America that reaches the northern extent of its range in Western Canada. It occurs at multiple sites in southeastern Alberta in the general area where the Bow, Oldman, and South Saskatchewan rivers come together. In Saskatchewan, it has been found at only one site just east of the Alberta border where the South Saskatchewan River joins the Red Deer River. Population trends for the Small-flowered Sand-verbena are difficult to interpret as abundance is heavily dependent on rainfall. Surveys of all known sites in 2001 revealed only two plants, whereas more than 3000 were counted on similar surveys done in 2002. Two new populations were discovered in Alberta in 2002, and one of the previously known populations is presumed to be extirpated. No plants were found at the site in Saskatchewan in either 2001 or 2002.



In Alberta and Saskatchewan, the Small-flowered Sand-verbena is found in the mixed-grass prairie region. It grows on sand-hill areas in very dry conditions, and usually requires some drifting or unstable sand. The largest populations occur on hard-packed, fine sand on level ground, but it is also found on slopes or the ridge tops of the dunes.



The Small-flowered Sand-verbena is an ephemeral species — when conditions are appropriate, it germinates, flowers, sets seed, and dies in a relatively short time. The extremely hardy seeds lay dormant awaiting suitable conditions for germination the following or subsequent spring, when the cycle is repeated. The Small-flowered Sand-verbena can only germinate when moisture is present for a sufficient length of time to break down the dispersal structure that covers its seeds. This prevents loss of seeds that might germinate in response to a spring storm that is followed by a hot dry period. Flowering occurs from May to July over the species’ range, but most plants in Canada flower in mid-June and produce fruit in mid-July. Since the Small-flowered Sand-verbena is an annual, and the seeds are winged, the plant is unlikely to be found in exactly the same spot each year. Natural dispersal will usually carry seeds downwind and downstream from the original site.



Dune stabilization has resulted in a significant loss of habitat for the Small-flowered Sand-verbena throughout its range in Canada. The absence of fire and the decreased grazing of prairie areas have resulted in less drifting or unstable sand, allowing the establishment of other species, including alien invasive weeds, on the dunes. The cultivation of areas surrounding existing populations of Small-flowered Sand-verbena also decreases the opportunities for it to spread naturally. One of the sites with the largest number of plants in 2002 is currently threatened by sand removal and leveling of the main dune area.



Federal Protection

The Small-flowered Sand-verbena 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 Small-flowered Sand-verbena (Tripterocalyx micranthus) in Canada
Status Final posting on SAR registry


Recovery Team

Prairie Plant Species at Risk Recovery Team

  • Candace Neufeld - Chair/Contact - Environment Canada
    Phone: 306-975-4101  Send Email



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 small-flowered sand-verbena Tripterocalyx micranthus in Canada (2002-05-01)

    Small-flowered sand-verbena Tripterocalyx micranthus (Torr.) Hook. is an annual species and a member of the four o'clock family (Nyctaginaceae). It is a much-branched plant, 2-5 dm high with trailing branches, up to 6 dm long, with ascending tips. The succulent, pale stems are enlarged at the nodes. The paired leaves are entire, somewhat round, and have prominent veins. Leaf blades are 2-6 cm long, 1-3 cm wide. The tiny greenish-white flowers are quite showy as they are arranged in dense clusters with a ring of bracts underneath. Flowers lack petals but have 5 petal-like lobes formed into a long tube, 5 mm in width. When the ovary ripens into the fruit, the base of the calyx tube becomes transformed into a winged structure, closely enclosing the fruit and aiding in its dispersal. These winged fruits are pale green with a pink blush. The fruit is about 2 cm long with 2-3 thin, papery, strongly veined nerves.

Response Statements

  • Response Statements - Small-flowered Sand-verbena (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 Small-flowered Sand-verbena (Tripterocalyx micranthus) in Canada (2012-11-30)

    The Species at Risk Act (SARA, Section 37) requires the competent minister to prepare recovery strategies for listed extirpated, endangered or threatened species. Small-flowered Sand-verbena was listed as endangered under SARA in January 2005. Environment Canada led the development of this Recovery Strategy. This recovery strategy was developed in cooperation or consultation with provincial jurisdictions in which the species occurs – Saskatchewan, Alberta; industry stakeholders; the Department of National Defence and Agriculture and Agri-Food Canada.


  • 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.

Permits and Related Agreements

  • Explanation for issuing permit(#27), persuant to the provisions of section 73 of SARA (2006-06-27)

    This is a rare plant survey to locate and enumerate populations of SARA listed plants on the Onefour Research Farm. Specimens of a plant will be collected only when required to verify the identification of the species.
  • Explanation for issuing permit(#SARA-PNR-2009-0108), persuant to the provisions of section 73 of SARA (2009-10-16)

    The purpose of the study is to determine sampling intensities required to detect this species in the soil seed bank, to determine how competition affects plants and seed production, to determine what portion of the seed bank remains dormant, and to understand productivity of plants along roadsides. The work is intended to aid in recovery planning for the species. Paired 10m X 2m sample plots will compare dirt road surfaces, adjacent roadsides and adjacent native prairie where plants are expected to occur. A series of 20 core samples will be taken at each sampling plot and individually sifted. The cores will be 10 cm wide by 10cm deep. The series of cores will be repeated until 5 seeds are found or until 5 repetitions are completed. Soil will immediately be returned to the hole where it was collected, and seeds will be broadcast on the plots. Up to 150 plots will be sampled three times throughout the year. Individual plants will be marked with adjacent plastic sticks to monitor plant survival, flowering and seed production. Control sites will be similarly sampled at Suffield and at AAFC OneFour. Part two of the study will examine the effect of burial depth on seedling emergence. Three hundred seeds currently held in cold storage at the Last Mountain Lake National Wildlife area will be planted in plots at 1 cm depth, 5 cm depth, and 10 cm depths and germinated at Last Mountain Lake.
  • Explanation for issuing permit(#SARA-PNR-2010-0157), persuant to the provisions of section 73 of SARA (2010-10-18)

    The activity consists of annual road grading along Rifleman's Road in the Komati training area of Canadian Forces Base Suffield. This grading will include approximately 1 km of roadway where small-flowered sand verbena occurs. The road will be graded using two graders with 14 foot blades. The two graders will each make one pass down one side of the road then return down the other side of the road. As a result, a 28 foot road will be maintained with four passes of the grader. The grader activity will be confined to the 28 foot swath mentioned above and the ditch area will not be disturbed.

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.

Critical Habitat Descriptions in the Canada Gazette

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