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Recovery Strategy for Multi-Species at Risk in Maritime Meadows associated with Garry Oak Ecosystems in Canada (Proposed)


Species Descriptions

1.12 Bearded-owl clover triphysaria versicolor ssp. versicolor

Assessment Summary – May 2000

Common name: bearded owl-clover

Scientific name: Triphysaria versicolor ssp. versicolor

Status: Endangered

Reason for designation: Disjunct with highly specific habitat requirements, few populations in restricted range, subject to development, risks from recreational activities and competition with exotic plants.

Occurence: British Columbia

Status history: Designated Endangered in April 1998. Status re-examined and confirmed in May 2000. May 2000 assessment based on new quantitative criteria applied to information from the existing 1998 status report.

1.12.1 The species

Triphysaria versicolor Fisch. & C. Meyer ssp. versicolor is a well-delineated taxon as described in the status report (Penny et al. 1996). T. versicolor ssp. faucibarbatus, the only other taxon within the species, is restricted to California (Chuang and Heckard 1993).

Bearded owl-clover is a small (10-50 cm) annual herbaceous plant with tiny hairs on the leaves and stems. The leaves are pinnately divided onto linear segments. The inflorescence, a terminal spike, has white or pink flowers and leaf-like bracts. The club-shaped corollas distinguish bearded owl-clover from narrow-leaved owl-clover (Castilleja attenuatus). It can be distinguished from dwarf owl-clover (T. pusilla), which is a smaller plant with more finely dissected leaf segments (Douglas et al. 2000; Penny et al. 2000). Bearded owl-clover is a root-parasite (hemiparasite) that appears to parasitize a broad range of host species.

1.12.2 Distribution

Bearded owl-clover ranges from southern Vancouver Island, south along the Pacific coast to southern California (Figure 3). The species is absent from Washington State and northern Oregon; the Canadian populations are disjunct, by about 500 km, from the next nearest populations in Lane County (Oregon). In the United States, bearded owl-clover is ranked SNR in California and Oregon, the only two states where it occurs (NatureServe 2004).

In Canada, the historical extent of occurrence covered approximately 95 km² and the current extent of occurrence is under 15 km². The COSEWIC status report estimates the area of occupancy to be 379  although since this report two newly documented populations (combined area under 200 ) place the total area of occupancy in Canada under 600 .

Figure 3. Global and Canadian distribution of bearded owl-clover
(Global distribution on left; Canadian distribution on right with open stars showing extirpated populations and solid stars showing locations of one or more extant populations)
Figure 3. Global and Canadian distribution of bearded owl-clover (Global distribution on left; Canadian distribution on right with open stars showing extirpated populations and solid stars showing locations of one or more extant populations)

1.12.3 Population and distribution trend

There are seven extant populations and one that has been extirpated. This has been confirmed using the description of populations from the BC Conservation Data Centre criterion for recognizing distinct populations (those separated by less than 1,000 m as subpopulations) in addition to subsequent surveys. The COSEWIC status report describes eight extant 'populations' and two or three other populations (the record from Mount Finlayson may have been based on a misidentification) which have not been reported for more than 80 years (Penny et al.1996).

The COSEWIC status report estimates a total population size of between 4,000 and 5,000 plants (Penny et al. 1996). Subsequent surveys (Table 11) of some populations indicated that their numbers may be higher, at least in favourable years.

Table 11. Population information for bearded owl-clover in Canada
PopulationLand TenureData from Status ReportSubsequent Data
DateObserver# PlantsDateObserver# Plants
Cedar Hillunknown1897HenryunknownNo further information
Mount Finlaysonunknown1908NewcombeunknownNo further information
Islands south of Victoriaunknown1915HigginsunknownMay be from the populations recently described from Mary Tod and/or Strongtide Islands
Ten Mile Pointprivate property1996Penny612002Penny> 1,900
Cattle PointMunicipality of Oak Bay (designated as an urban park)1996Penny1,300Mapped in 2003 but not counted
Victoria Golf Clubprivate property1996Penny3002004Fairbarns250-400
Harling Pointprivate property designated a National Historic Site1996Penny672002Fairbarns270
Glencoe CoveMunicipality of Saanich (designated as an urban park)1996Penny2,5002001Penny4,100
Mary Tod IslandMunicipality of Oak Bay (designated as an urban park)Population unknown when status report written2001Douglas6
Strongtide IslandSonghees Indian ReservePopulation unknown when status report written2003Fairbarns500-1,000

1.12.4 Biotic and abiotic features of habitat

Bearded owl-clovergrows in maritime meadows and seepages. It is largely restricted to low sites <10 m above sea level and within 30 m of the shoreline. It occurs in rocky areas and moderately shallow soils and its habitat is often maintained open by a combination of salt spray, wind, summer drought and winter seepage, which combine to prevent trees, shrubs and more robust herbs from becoming established. It occurs in vegetation dominated by grasses and forbs. The sites have not been ploughed in the past but often contain large amounts of invasive alien pasture grasses including orchard-grass (Dactylis glomerata), barren brome (Bromus sterilis), soft brome (B. hordeaceus), sweet vernalgrass (Anthoxanthum odoratum), hedgehog dogtail (Cynosurus echinatus) and common velvet-grass (Holcus lanatus). The meadow soils are fresh or wet throughout the winter months but dry to the permanent wilting point by mid-summer.

1.12.5 Annual cycle

Bearded owl-clover is an annual plant. Unpublished notes (M. Fairbarns 2003 and 2004) have documented the annual cycle.

Unpublished notes (M. Fairbarns 2003 and 2004) from Harling Point, Victoria Golf Club, Glencoe Cove and Strongtide Island reveal the following cycle. Germination begins in January. At least some seedlings, bearing nothing but cotyledons, are found as late as mid-March. True leaves are evident on rapidly growing plants by as early as February. Most plants are dead by late June. Flowering begins in April and may continue until late May. Fruit development begins in late April and seed dispersal in some plants continues into July.