Species Profile

Dense Spike-primrose

Scientific Name: Epilobium densiflorum
Taxonomy Group: Vascular Plants
COSEWIC Range: British Columbia
COSEWIC Assessment Date and Status Change: May 2005
COSEWIC Status: Endangered
COSEWIC Status Criteria: A3c; B1ab(i,ii,iii,iv,v)+2ab(i,ii,iii,iv,v)
COSEWIC Reason for Designation: An annual herb of a restricted habitat type within the Garry Oak Ecosystem that has undergone significant declines in number of populations and is subject to continued habitat reduction due to development and the spread of exotic weeds. The four extant populations are fragmented, small, and have little chance of being repopulated from adjacent sites in Washington State should they become extirpated.
COSEWIC History of Status Designation: Designated Endangered in May 2005.
SARA Status: Schedule 1, Endangered
Date of Listing (yyyy-mm-dd): 2006-08-15

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: | Description | Distribution and Population | Habitat | Biology | Threats | Protection | Recovery Initiatives | Recovery Team | National Recovery Program | Documents


The Dense Spike-primrose is an annual herb measuring 15 to 100 cm in height. The plant is covered with numerous white hairs and its stems sometimes branch upward. Its leaves alternate around the stem, except near the taproot, and have almost no stalk. Long, lance-shaped and relatively wide at the base, they are smooth-edged or finely serrated. The small flowers, ranging from white to rose-purple, are arranged in a number of leafy spikes along the sides and at the top of the plant. At maturity, the plant produces dry fruit, which consists of capsules containing several seeds. The seeds of this species lack the tufts of silky hair common to most species of the genus. The Dense Spike-primrose can be mistaken for the Brook Spike-primrose, a related species at risk that also has hairless seeds.


Distribution and Population

In North America, the Dense Spike-primrose is found from Vancouver Island, the southern Gulf Islands and the state of Washington south to Baja California and east to Idaho, Utah and Nevada. In Canada, the species is found in southwestern British Columbia, from Victoria to Nanaimo. The nearest population outside Canada is 20 km south, on San Juan Island in the state of Washington. Suitable habitats have been heavily studied in the past 20 years, revealing a sharp decline in the number of populations. Today, only four remaining Canadian populations are known, one of which had only one reproductive plant in 2003. The four Canadian populations have an aggregate of about 2800 to 3400 individuals. The populations are extremely small and fragmented and it is unlikely that any exchanges will occur between these populations and those in the United States due to the low capacity of seed dispersion, as the seeds do not have any mechanism to facilitate their dispersion by the wind.



In Canada, the Dense Spike-primrose occurs in a limited area within the Garry Oak ecosystem. It is found in roadside ditches and in open meadows that are moist in spring but very dry during most of the summer. An estimated 95% of its potential habitat has been lost over the past century due to agricultural, urban and industrial development, along with fire suppression and invasion by exotic grasses and shrubs. Areas suitable for the Dense Spike-primrose have likely experienced declines similar to those of Garry Oak ecosystems in terms of surface area and quality.



The Dense Spike-primrose is an annual that flowers from June to August and fruits in mid- to late summer. It is predominantly self-pollinated but pollen may also be transferred from flower to flower by insects, especially bees. The seeds are dispersed from the capsules in the late fall and winter. Unlike most of its close relatives, this plant bears seeds that lack a tuft of hairs. As a result, the seeds are not widely dispersed by the wind and likely fall to the ground not far from the parent plant. The seeds germinate during the wet season, in winter or the following spring, but the plant continues to develop well into the summer dry period characteristic of southeast Vancouver Island. The ability to tolerate very high moisture levels in the winter and very low moisture levels in the summer allows this plant to grow where many others could not.



The primary threat to the Dense Spike-primrose in Canada is the destruction of its habitat, which is located in one of the fastest-growing urban areas in North America. Its highly restricted habitat is thus being destroyed by residential and recreational development. The last large population is threatened in the short term by a proposed trailer park development. Expansion of the species is limited by the fact that it requires a dry summer and a very wet, mild winter¾conditions only found along a very restricted fringe of coastal habitat on southeast Vancouver Island and neighbouring islands. The four extant populations and most of the historic populations are in fact found near the Pacific Ocean, warmed by the waters of the California Current, which moderates temperatures in winter. The habitat of the Dense Spike-primrose is also affected by changes in hydrology and invasive exotic plants that present numerous threats to the species. The tallest species threaten to choke the Dense Spike-primrose by depriving it of sunlight, whereas other species may use up the moisture and nutrients. What’s worse, annual exotic plants colonize recently disturbed areas that could have served for the germination of Dense Spike-primrose seeds.



Federal Protection

The Dense Spike-primrose 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 Dense Spike-primrose has no provincial protection in British Columbia. Only one of the four extant Canadian populations is located in a provincial park.

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 Dense Spike-primrose (Epilobium densiflorum) in Canada
Status Final posting on SAR registry


Recovery Team

Garry Oak Ecosystems Recovery Team

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

10 record(s) found.

COSEWIC Status Reports

  • COSEWIC assessment and status report on the dense spike-primrose Epilobium densiflorum in Canada (2005-08-12)

    Epilobium densiflorum is a densely white-hairy annual herb arising from a taproot. Its leaves are essentially stalkless and alternate varying from elongate lance-shaped to ovate-lanceolate within the inflorescence. The rose-purple flowers are arranged in lateral spikes subtended by leafy bracts. The ripe capsules contain several seeds within each of the four chambers. Characteristically, the seeds lack the tuft of hairs (coma) that are present in most species of the genus.

Response Statements

  • Response Statements - Dense Spike-primrose (2005-11-15)

    An annual herb of a restricted habitat type within the Garry Oak Ecosystem that has undergone significant declines in number of populations and is subject to continued habitat reduction due to development and the spread of exotic weeds. The four extant populations are fragmented, small, and have little chance of being repopulated from adjacent sites in Washington State should they become extirpated.

Recovery Strategies

  • Recovery Strategy for the Dense Spike-primrose (Epilobium densiflorum) in Canada (2013-08-19)

    Dense Spike-primrose (Epilobium densiflorum) is listed as Endangered under Canada's Species at Risk Act (SARA). Dense Spike-primrose is an annual herb, which measures 15-100 cm in height with a hairy stem and small white to rose-purple flowers. It is restricted to western North America: from southern British Columbia to southern California east to Utah and Idaho. The species is listed as globally secure. Within its range, it is restricted to ephemerally wet areas associated with Garry Oak ecosystems. There are historical records for 20 occurrences over a 2,000 km² range in Canada, but Dense Spike-primrose has been reduced to four extant occurrences over a 900 km² range. The entire Canadian population (all four occurrences) occupies a total of 10 ha and consists of approximately 102,120 plants.


COSEWIC Annual Reports

  • COSEWIC Annual Report - 2005 (2005-08-12)

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

Permits and Related Agreements

  • Explanation for issuing permit(#SARA-PYR-2009-0121), persuant to the provisions of section 73 of SARA (2009-10-06)

    The proposed activity is to continue tilling the fire break at Canadian Forces Ammunition Depot (CFAD) Rocky Point, while managing for a newly discovered plant species at risk. The activity of tilling will take place within the established firebreak zone at CFAD Rocky Point. The firebreak is located around the perimeter fence that separates the ammunition storage depot from the remainder of the CFAD Rocky Point property. The Dense Spike-primrose is currently found in the firebreak on the west and north side of the compound.
  • Explanation for issuing permit(#SARA-PYR-2009-0126), persuant to the provisions of section 73 of SARA (2010-02-04)

    The goal of this project is to protect selected populations of rare species from habitat degradation due to invasive species or conifer encroachment. The species include: Bartramia stricta, Rigid Apple Moss Dryopteris arguta, Coastal Wood Fern Enthostodon fascicularis,Banded Cord-moss Epilobium densiflorum, Dense Spike-primrose Limnanthes macounii ,Macoun's Meadowfoam Lotus formosissimus, Seaside Birds-foot Lotus Lupinus densiflorus, Dense-flowered Lupine Meconella oregano, White Meconella Microseris bigelovii, Coast Microseris Minuartia pusilla, Dwarf Sandwort Ranunculus alismifolius, Water-plantain Buttercup Sanicula arctopoides, Bear's-foot Sanicle Sanicula bipinnatifida, Purple Sanicle Tortula laevipila, Twisted Oak Moss The permit proposal is for multi-year species at risk (SAR) stewardship activities at several Department of National Defence (DND) properties on Southern Vancouver Island. The SAR at each site occur in open meadows that are being encroached by invasive species such as: Scotch broom, English ivy, gorse, English holly, Daphne spurge, English hawthorn, herbaceous annual and biennial weeds, annual and perennial grasses and/or conifers. The goal is to remove the invading species from the area within and adjacent to the selected SAR populations.

Consultation Documents

  • Consultation on Amending the List of Species Under the Species At Risk Act: November 2005 (2005-11-16)

    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.


  • Public Registry Notice for s.83 Exceptions - CFB Esquimalt (2015-03-06)

    Operations directed to ensuring that training areas are sustainable for activities related to national defence/security. Specifically, the exceptions apply to activities for the control and management of vegetation that interferes with, or restricts, training.
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