BC Conservation Data Centre: Species Summary
Limnanthes macounii
Macoun's meadow-foam
| Scientific Name: | Limnanthes macounii Trel. | ||||||||||
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| English Name: | Macoun's meadow-foam | ||||||||||
| Classification / Taxonomy | |||||||||||
| Scientific Name - Concept Reference: | Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR. | ||||||||||
| Classification Level: | Species | ||||||||||
| Species Group: | Vascular Plant | ||||||||||
| Species Code: | LIMNMAC | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G2? (Feb 2026) | ||||||||||
| Provincial Status: | S3 (Apr 2025) | ||||||||||
| BC List: | Blue | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Special Concern (Dec 2023) | ||||||||||
| SARA Schedule: | 1 - Threatened (Aug 2006) | ||||||||||
| General Status Canada: | 1 - At Risk (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | There are no subspecies of Limnanthes macounii documented or recognized in B.C. | ||||||||||
| Identification Comments: | Limnanthes macounii is a small annual herb, 2-5 cm tall (up to 15 cm) with erect or decumbent unbranched glabrous stems. It has glabrous basal and cauline leaves that are 1-7 cm long and are pinnate with 3-13 lobed segments. Flowers are single, tetramerous (sometimes pentamerous), funnelform or rotate, protandrous, and approximately 7-10 mm in diameter. Sepals (4) are ovate, acute, green, and 3-4 mm long. Petals (4) are obovate, slightly emarginate, and white with two rows of hairs at the base. Flowers have 8 stamens, 4 pistils (with almost free ovaries), and 4 elongate stigmas. Fruits are 3-4 nutlets, obconical, tuberculate on the tip, and yellow-green to brown (Ceska and Ceska 2003). | ||||||||||
| Similar Species: | When in flower, Limnanthes macounii can be easily identified by its pinnate leaves and four-part flowers, but when lacking flowers it can be confused with four other taxa: Lepidium virginianum ssp. menziesii, Cardamine spp., Nemophila parviflora, and Nemophila pedunculata (Ceska and Ceska 2003). L. macounii can be distinguished from the first two species by the lack of a tap root and the presence of totally glabrous leaves. It differs from Nemophila species in having glabrous pinnate leaves (vs. non-glabrous, pinnatisect leaves). | ||||||||||
| Provincial Reproduction Comments: | Because it is an annual plant, persistence of the Limnanthes macounii population depends on sexual reproduction. Plants are protandrous - anthers develop before stigmas become receptive to pollen. The structure of Limnanthes flowers indicates that the genus was originally insect pollinated. Gland-like swellings at the base of the stamens, hairs at the base of petal claws, and patterning in UV light are all features associated with insect pollination. Several insects (saw-flies, ants, earwigs, and lady bugs) have been observed on or near the plants (Ceska and Ceska 1988). Limnanthes macounii has become autogamous, perhaps due to lack of pollinators during flowering (early spring is generally cold, rainy, and windy) (Ceska and Ceska 1988). Even though flowers are protandrous, there is a time when stigmas easily come in contact with anthers during flower development; therefore, L. macounii is most likely self-pollinated and produces fruit without any cross-pollination. Isozyme studies on subpopulations in three localities of L. macounii in B.C. have revealed genetic uniformity among subpopulations and localities, which is another indicator of autogamy (Ceska and Ceska 1988). | ||||||||||
| Provincial Ecology Comments: | Limnanthes macounii is a winter annual, which gives it an advantage because it can germinate and produce biomass when other competing species are dormant. Winter weather can, however, affect survival of the species because it passes through juvenile stages of development during this time. In severe winters, many plants die, especially those that are submerged in vernal pools. Even during moderate winters, a good portion of the population may not survive. Ceska and Ceska (2003) reported that the species is most likely barochoric - large nutlets fall from plants in the vicinity of the parent and are not dispersed by a dispersal agent. Poor dispersal capability is considered to be the most important factor that restricts the distribution of Limnanthes macounii and the genus, in general (Ceska and Ceska 1988). Three to four fairly large nutlets are produced by each flower most years. Shaded plants produced fewer nutlets. Seeds exhibit a strong dormancy, a characteristic of annual species. Seed germination is likely triggered by cold temperatures, which is the case for other species of Limnanthes (Ceska and Ceska 2003). L. macounii requires bare open soil and sufficient moisture during its vegetative period; therefore, it is sensitive to competition, especially from introduced grasses that form tussocks or dense swards. These introduced grasses directly compete with L. macounii by occupying bare soil and accumulating biomass in depressions (filling in vernal pools), which makes them drier and less suitable for growth and reproduction of L. macounii. Introduced shrubs and species that form basal rosettes can directly compete with L. macounii through shading and occupying open bare soil, respectively. Winter annual introduced species that have the same phenology as L. macounii are also major competitors. No insect or mollusc pests have been observed or reported for L. macounii. The species responds well to soil disturbance: bird pecking and human traffic help reduce competition from introduced species and maintain a suitable amount of open soil. Grazing has also been shown to benefit the growth and survival of L. macounii (Ceska and Ceska 2003). In a restoration experiment, Ceska and Ceska (2003) and others mowed populations that were undergoing heavy grass competition and removed grass foliage and sods with rakes, including accumulated organic biomass. The populations recovered well by germinating from the existing seed bank. | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Forest / Deciduous/Broadleaf Forest / Facultative - occasional use
Grassland/Shrub / Garry Oak Maritime Meadow / Facultative - frequent use Grassland/Shrub / Meadow / Facultative - frequent use Other Unique Habitats / Garry Oak Vernal Pool / Facultative - frequent use |
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| Global Habitat Comments: | Vernal pools, seepage areas on rocky slopes, wet depressions in open Douglas fir forests. | ||||||||||
| Provincial Habitat Comments: | Limnanthes macounii occurs in seasonally wet (i.e. dry in summer and wet in winter) pools and depressions or in seepage streams and slopes at low elevations in coastal areas of Vancouver Island and the adjacent islands (Ceska and Ceska 2003). Most sites are in open areas, but several sites are in wet depressions in very open Douglas-fir, Garry oak, and arbutus forests. Other populations are located in open mixed forests of Douglas-fir, Garry oak, arbutus, Rocky Mountain juniper, or lodgepole pine. Depressions in shallow soil-lining bedrock (a form of vernal pool) and intermittent seepage streams along fractures in bedrock typically have water regimes that are suitable for the growth of Limnanthes macounii (Ceska and Ceska 2003). Bedrock is mostly volcanic but sometimes is sandstone; it is impermeable and has 0-15 cm of glacial till deposits. Limnanthes macounii grows in shallow soils (3-30 cm deep) that are rich in humus and nutrients. The temperate Mediterranean climate where the species occurs is characterized by mild winters and dry, warm summers, with most precipitation falling during the winter months. The habitat of Limnanthes macounii often occurs in Garry oak ecosystems, part of the drier subzone of the Coastal Douglas-fir zone (CDFmm) (Douglas et al. 2002). Associated species include Aphanes occidentalis, Brodiaea coronaria, Camassia quamash, Dodecatheon parviflorum, and Montia fontana, as well as a host of introduced species. | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
Jan: Vegetative / Vegetative
Feb: Vegetative / Vegetative Mar: Vegetative / Vegetative, Flowering Apr: Vegetative, Flowering / Vegetative, Flowering May: Vegetative, Flowering / Vegetative, Flowering Jun: Vegetative, Fruiting / Vegetative, Fruiting Sep: / Germinating Oct: Germinating / Germinating Nov: Vegetative, Germinating / Vegetative, Germinating Dec: Vegetative / Vegetative |
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| Provincial Phenology Comments: | Limnanthes macounii is a winter annual which germinates in the autumn after the first heavy rains (late September through November, with some germination continuing through winter), flowers by late March, and produces fruit and dies in June; therefore, it is dormant and seeds are "at rest" during the droughty summer. | ||||||||||
| Elevation (m) (min / max): | Provincial: 5 / 195 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | D - Low | ||||||||||
| Ownership of occurrences (Known locations): | Mixed private/government | ||||||||||
| Inventory Need: | The likelihood of finding many new localities of Limnanthes macounii is low, particularly in the Victoria area. New localities may be found on infrequently visited or remote Gulf Islands, or on coastlines of Vancouver Island that have not been visited by the Ceskas or other expert botanists. | ||||||||||
| Inventory Comments: | Adolf and Oldriska Ceska have inventoried and monitored Limnanthes macounii on southern Vancouver Island and adjacent islands since the early 1970s. Suitable sites have been repeatedly surveyed by the Ceskas and other expert botanists since the early 1980s in a series of projects designed to document rare plants in open meadow communities in southeast Vancouver Island and the Gulf Islands (Fairbarns et al. 2004). Garry oak recovery strategy projects have enabled a concerted inventory of habitats such as vernal pools and seepage areas, preferred habitat for Limnanthes macounii, in recent years. | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | There are no known economic uses for Limnanthes macounii in B.C. Species of Limnanthes contain lipids, C22 fatty acids, similar to those contained in sperm whale oil and jojoba seeds. These lipids were once quite valuable but have decreased in value since the creation of new synthetic oils. | ||||||||||
| Distribution | |||||||||||
| Endemic: | Y | ||||||||||
| Global Range Comment: | This species is endemic to British Columbia, known from Vancouver Island and adjacent islands in British Columbia from East Sooke Park to Victoria, Inskip, Chatham, and Trial islands, to Yellow Point, Saltspring, Gabriola, and Hornby islands. | ||||||||||
| Disjunct, more common elsewhere: | N | ||||||||||
| Peripheral, major distribution elsewhere: | N | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | |||||||||||
| Provincial Information Author: | Bartemucci, P. | ||||||||||
| Last Updated: | Feb 18, 2005 | ||||||||||
| Last Literature Search: | |||||||||||
| References and Related Literature | |||||||||||
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC. |
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Ceska, A., and O. Ceska. 1988. Status Report on Macoun's Meadowfoam, Limnanthes macounii, in Canada. Unpubl. rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 44pp. |
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Ceska, A., and O. Ceska. 2003c. Update COSEWIC Status Report on Macoun's Meadowfoam, Limnanthes macounii, in Canada. Unpublished rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. Draft. 32 pages. |
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COSEWIC. 2004l. COSEWIC assessment and update status report on the Macoun's meadowfoam Limnanthes macounii in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. vi + 24pp. |
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Douglas, G.W. 1996. Endemic Vascular Plants of British Columbia and Immediately Adjacent Regions. Can. Field-Nat. 110(3):387-391. |
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Douglas, G.W., D. Meidinger, and J. Penny. 2002. Rare Native Vascular Plants of British Columbia, 2nd ed. B.C. Conserv. Data Centre, Terrestrial Inf. Branch, Victoria. 358pp. |
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Douglas, G.W., D. Meidinger, and J. Pojar. eds. 1999. Illustrated Flora of British Columbia, Vol. 3, Dicotyledons (Diapensiaceae through Onagraceae). B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria. 423pp. |
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Fairbarns, M., A. MacDougall, A. Ceska and O. Ceska. 2004. COSEWIC status report on Coastal Silverpuffs, Microseris bigelovii, prepared for Comm. on the Status of Endangered Wildl. in Can. Funding provided by the Garry Oak Ecosystem Recovery Team and the BC Conservation Data Centre. 20 pp. |
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Fuchs, Marilyn A. 2001. Towards a Recovery Strategy for Garry Oak and Associated Ecosystems in Canada: Ecological Assessment and Literature Review. Tech. Rep. GBEI/EC-00-030. Environ. Can., Can. Wildl. Serv., Pac. and Yukon Region. |
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Please visit the website Conservation Status Ranks for definitions of the data fields used in this summary report.
Suggested Citation:
B.C. Conservation Data Centre. Species Summary: Limnanthes macounii. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 17, 2026).