BC Conservation Data Centre: Species Summary
Hosackia gracilis
seaside bird's foot lotus
| Scientific Name: | Hosackia gracilis Benth. | ||||||||||
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| Scientific Name Synonyms: |
Lotus formosissimus
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| English Name: | seaside bird's foot lotus | ||||||||||
| 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 | ||||||||||
| Taxonomy Comments: | English name changed to Seaside Bird's-foot Lotus in 2010 to be consistent with COSEWIC. True trefoils are so-named because their lowest pair of leaflets are basal and resemble stipules (their true stipules are tiny glands). In contrast, what we have called L. pinnatus and L. formosissimus have decent stipules and usually have 5 or more leaflets so they are not trefoils (M. Fairbarns, pers. comm. 2010). | ||||||||||
| Species Group: | Vascular Plant | ||||||||||
| Species Code: | HOSAGRA | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G4 (Feb 2005) | ||||||||||
| Provincial Status: | S2 (Apr 2019) | ||||||||||
| BC List: | Red | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Endangered (Nov 2010) | ||||||||||
| SARA Schedule: | 1 - Endangered (Jun 2003) | ||||||||||
| General Status Canada: | 1 - At Risk (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | Lotus formosissimus is a well defined taxon with no recognized subspecies in Canada. | ||||||||||
| Identification Comments: | Lotus formosissimus is a sprawling to ascending perennial (20-50 cm long) which grows from a thick taproot. The leaves are petiolate, 4-8 cm long with ovate to obovate leaflets. The stipules are membraneous, rounded to acuminate, and the flowering stems usually have 3 (1-5 or 7) foliate bracts at the tip. The flowers are pea-like with a yellow banner, pinkish to purplish-tinged wings, and a purple-tipped keel. There are 10 other Lotus species in Canada, 9 of which occur in British Columbia. | ||||||||||
| Similar Species: | In B.C., Lotus corniculatus, L. denticulatus, L. micranthus, L. nevadensis, L. pedunculatus, L. pushianus, and L. tenuis have reduced stipules represented by blackish glands, whereas L. formosissimus has membraneous stipules. L. pinnatus in B.C. has yellow and white flowers and lacks a foliar bract, whereas L. formosissimus has yellow and pink flowers and often has foliar bracts. | ||||||||||
| Provincial Reproduction Comments: | Grazing significantly decreases growth and reproduction of Lotus formosissimus. Seed predation was found during field studies. At least 6 of 44 capsules were attacked by insects and lost all of their seeds. Seedling mortality is high; few plants survive the first summer drought after germination. Seeds of L. formosissimus experience dormancy, and large numbers of seeds may be banked for at least one year. Flowers are pollinated by bumblebees (Fairbarns 2005f). The status report states that the species appears to require cross-pollination to produce viable seeds (Ryan and Douglas 1996c). | ||||||||||
| Provincial Ecology Comments: | The status report suggests that like other legumes, Lotus formosissimus may be associated with nitrogen-fixing Rhizobium bacteria. This has been confirmed by field studies. The nodules of many Fabaceae perennials are shed when the shoots die back or if the plants are heavily grazed or mowed (Fairbarns 2005f). | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Grassland/Shrub / Garry Oak Maritime Meadow / Facultative - frequent use
Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - occasional use |
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| Provincial Habitat Comments: | The habitat of Lotus formosissimus consists of mesic maritime meadows which are affected by the sub-Mediterranean climate caused by the rain shadow of the Olympic and Vancouver Island mountains. Habitat ranges from nearly level to moderate southeast to southwest slopes, and the meso slope position is either level or on the lower slope. Soils are generally more than 20 cm deep and are moderately well to well drained. Vegetation type is dry meadow, mesic meadow, or mesic open deciduous or coniferous woodland. There may be a sparse canopy of Quercus garryana, Pinus contorta, Arbutus menziesii, and/or Pseudotsuga menziesii, but trees are generally absent due to wind exposure, salt spray, and shallow soils. Native shrubs, including Symphoricarpos albus, Rosa nutkana, and/or Gaultheria shallon, may form thickets at the edge of populations or may be sparse or absent. Exotic invasive shrubs are abundant in some locations. The herb layer is typically dominated by a mix of native and introduced species. A study to identify critical components of suitable habitat for L. formosissimus has been completed (Fairbarns 2005f). | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
Jan: Vegetative / Vegetative
Feb: Vegetative / Vegetative Mar: Vegetative / Vegetative, Germinating Apr: Vegetative, Germinating, Flowering / Vegetative, Germinating, Flowering May: Vegetative, Germinating, Flowering / Vegetative, Flowering Jun: Vegetative, Flowering / Vegetative, Flowering, Fruiting Jul: Vegetative, Fruiting / Vegetative, Fruiting Aug: Fruiting / Fruiting Nov: Vegetative / Vegetative Dec: Vegetative / Vegetative |
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| Provincial Phenology Comments: | Shoot dormancy is broken at different times at different sites. Shoots protected under leaf litter on Trial Island broke dormancy as early as mid-November, whereas on Bentinck Island, shoots broke dormancy in mid-February. Leaves unfolded in late February or early March and remained prostrate until May. Most shoots died back by late July or early August and the onset of summer drought. Most seedlings germinated from early April to mid May, although germinants were found as early as December in ex situ experiments. Flower buds formed in April or May and peaked in June. Green fruit were abundant in June and dispersed in August (Fairbarns 2005f). | ||||||||||
| Elevation (m) (min / max): | Provincial: 1 / 25 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | C - Moderate | ||||||||||
| Ownership of occurrences (Known locations): | Mostly national government | ||||||||||
| Inventory Need: | Although Lotus formosissimus is relatively easy to identify and is showy when in flower, further inventory is still required. | ||||||||||
| Inventory Comments: | Two populations of Lotus formosissimus which could not be verified in the status report (Ryan and Douglas 1996c) have since been confirmed to have extant populations. This emphasizes the need for further inventory. | ||||||||||
| Economic Attributes | |||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Disjunct, more common elsewhere: | Y | ||||||||||
| Peripheral, major distribution elsewhere: | Y | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | |||||||||||
| Provincial Information Author: | C. Maslovat | ||||||||||
| Last Updated: | Feb 28, 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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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. 2005f. Demographic and Phenological Patterns of Lotus formosissimus (Seaside Bird's-foot Trefoil). Aruncus Consulting, 776 Falkland Road, Victoria, BC. |
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Maslovat, C. 2009. Guidelines for Translocation of Plant Species at Risk in British Columbia. B.C. Minist. of Environ. Victoria, BC. |
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Ryan, M., and G.W. Douglas. 1996c. Status Report on Seaside Birds-foot Lotus, Lotus formosissimus, in Canada. Unpubl. rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 25pp. |
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Ward, M. and R. Bittman. 2004. Rare Plant Status Review: Lotus formosissimus. California Native Plant Society and California Natural Diversity Database. September 2, 2004. |
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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: Hosackia gracilis. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 5, 2026).