Species Profile

Small-flowered Tonella

Scientific Name: Tonella tenella
Taxonomy Group: Vascular Plants
Range: British Columbia
Last COSEWIC Assessment: November 2003
Last COSEWIC Designation: Endangered
SARA Status: Schedule 1, Endangered


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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 Tonella

Small-flowered Tonella Photo 1

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Description

The Small-Flowered Tonella is a slender, delicate plant (as its French common name suggests). It is a sprawling, annual herb that sometimes ascends toward the tip and swivels on a fine taproot. The stems are hairless, often branched, and reach a height of 5 to 25 cm. The leaves are smooth or covered with soft short hairs on the upper surface and are arranged in opposing pairs along the stem. The lowermost leaves are rounded and slightly toothed. They are 1 to 2 cm long and have a small stalk called the petiole. The middle and upper leaves have three deep lobes that become narrower toward the top of the plant. The petioles become gradually shorter until they are completely absent on the small, smooth-edged, uppermost leaves. The flowers, which are blue and white and 2- to 4-mm wide, are on long stalks with few or no hairs. They occur singly or in groups at the angle of the bracts (the small leaves that accompany them). The corolla, or whorl composed of all the petals, forms two lips inserted into a short tube. The upper lip is two-lobed and the lower lip is three-lobed, with the middle lobe being larger than the two others. The calyx, composed of the sepals or small leaves at the base of the flower, is up to 3 mm long, longer than the tube of the corolla, and deeply five-lobed. The four stamens are protruding, and the fruit are dry ovate to globe-shaped capsules containing two to four wingless seeds 1 to 1.5 mm long.

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Distribution and Population

The main distribution range of the Small-Flowered Tonella is in the United States, extending from the Columbia River gorge in southern Washington southward through Oregon into central California. In Canada, the species is found only on the west side of Saltspring Island in the Gulf Islands of southwestern British Columbia. This location is disjunct from the main range of this annual herb. In 2002, four small sub-populations of Small-Flowered Tonella were observed on Saltspring Island, on the slopes of a mountain where another sub-population had been observed in 1976 but not relocated since. Each of these sub-populations comprised 30 to 150 plants and occupied an area ranging from 1 m2 for the smallest to approximately 40 m2 for the largest. The total population comprises approximately 230 to 315 plants and occupies a total area of 65 m2. The lack of data makes it impossible to detect the trend for this population. Other habitats that might shelter it have been explored, but without success. Because this plant is inconspicuous and very hard to spot, it is quite likely that other sub-populations do occur on this slope.

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Habitat

In British Columbia, the Small-Flowered Tonella occurs on west-facing slopes, on gravelly outcrops or stable talus. It is also found in open bigleaf-maple-arbutus forests and in open Douglas-fir-arbutus-Garry oak forests.

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Biology

Little information is available about the biology of the Small-Flowered Tonella. This herbaceous plant is an annual known to be capable of self-pollination, meaning that the plant can fertilize its flowers with its own pollen and, consequently, does not need neighbouring plants to reproduce. In the Small-Flowered Tonella, as in other small-flowered species, the tips of the pollen-bearing anthers come in contact with the stigmas (the part of the female reproductive organ of the flower where the pollen germinates) as soon as the flower begins to open. In this way, the plant can self-pollinate without waiting. The stigma are soon ready to receive the grains of pollen that fertilize the flowers. The fertilized flower turns into a small dry fruit containing two to four seeds. These seeds become sticky when wet and are probably dispersed by animals. The persistence of the Small-Flowered Tonella in British Columbia demonstrates that its seeds are viable and germinate readily. At low elevations, the plant is also pollinated by several insect species, including bumblebees.

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Threats

In British Columbia, the most immediate threat to the Small-Flowered Tonella population is habitat loss due to residential construction along the coast. The only site where the species occurs is on private waterfront property in an area where such property is the most highly prized. If this property were to be developed, the plant’s habitat would probably be reduced or completely destroyed. The loss of this site would thus mean the disappearance of this species from British Columbia and from Canada. Fires could also affect the survival of the Small-Flowered Tonella. The vegetation in the area where this species grows would be maintained by the natural pattern of fires of natural and human origin. The absence of fires allows combustible materials to accumulate, and a fire under these conditions would prove devastating. The drought conditions prevailing in British Columbia over the past few years have caused numerous fires. A fire occurring at the plant’s Saltspring Island site could wipe it out completely. The presence of exotic species also constitutes a threat to the Small-Flowered Tonella. The vegetation in the area where this species occurs is heavily dominated by introduced grasses.

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Protection

Federal Protection

The Small-flowered Tonella 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.

The Small-Flowered Tonella is not protected by any provincial laws in British Columbia.

Provincial and Territorial Protection

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

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Recovery Initiatives

Status of Recovery Planning

Recovery Strategies :

Name Recovery Strategy for Multi-species at Risk in Garry Oak Woodlands in Canada
Status Final posting on SAR registry

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Recovery Team

Garry Oak Ecosystems Recovery Team

  • Conan Webb - Chair/Contact - Parks Canada
    Phone: 250-478-5153  Send Email

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Documents

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.

8 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the small-flowered tonella Tonella tenella in Canada (2003)

    Tonella tenella (small-flowered tonella; Figwort family) is a slender, ascending to sprawling, annual herb from a delicate taproot. The smooth, often branched stems are 5-25 cm tall with opposite leaves. The leaves are smooth (or soft-hairy on the upper surface). The lowermost leaves are stalked, ovate to round, 1-2 cm long and few-toothed. The middle and upper leaves become un-stalked upward and are deeply 3-lobed with the segments progressively narrowing upward. The uppermost leaves are reduced and often entire. The inflorescence consists of one to several long-stalked flowers in the axils of the bracts with smooth or minutely glandular-hairy stalks. The corollas are blue and white, short-tubular, 2-4 mm wide, and 2-lipped with the upper lip 2-lobed, the lower lip 3-lobed, and the middle lobe the largest. The calyces are up to 3 mm long, and deeply 5-lobed with the lobes longer than the tube. The 4 stamens are exserted and the fruits are ovate to globe-shaped capsules. The 2 to 4 seeds are large, 1-1.5 mm long and wingless.

COSEWIC Assessments

Response Statements

Recovery Strategies

  • Recovery Strategy for Multi-Species at Risk in Garry Oak Woodlands in Canada (2016)

    This strategy has been developed under the broader Recovery Strategy for Garry Oak and Associated Ecosystems and their Associated Species at Risk in Canada: 2001-2006 (GOERT 2002) to address the recovery of five plant species at risk that occur within Garry oak (Quercus garryana) woodland habitat: deltoid balsamroot (Balsamorhiza deltoidea), white-top aster (Sericocarpus rigidus), small-flowered tonella (Tonella tenella), Howell's triteleia (Triteleia howellii), and yellow montane violet (Viola praemorsa ssp. praemorsa).

Orders

  • Order Acknowledging Receipt of the Assessments Done Pursuant to Subsection 23(1) of the Act (2004)

    The 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 (2005)

    The Minister of the Environment is recommending, pursuant to section 27 of the Species at Risk Act (SARA), that 43 species be added to Schedule 1, the List of Wildlife Species at Risk. This recommendation is based on scientific assessments by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC) and on consultations with governments, Aboriginal peoples, wildlife management boards, stakeholders and the Canadian public.

COSEWIC Annual Reports

  • COSEWIC Annual Report - 2004 (2004)

    2004 Annual Report to the Canadian Endangered Species Conservation Council (CESCC) from the Committee on the Status of Endangered Wildlife in Canada.

Consultation Documents

  • Consultation on Amending the List of Species under the Species at Risk Act: November 2004 (2004)

    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.