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BC Conservation Data Centre: Species Summary


Hosackia pinnata
bog bird's-foot trefoil

 
Scientific Name: Hosackia pinnata (Hooker) Abrams
Scientific Name Synonyms: Lotus pinnatus
English Name: bog bird's-foot trefoil
English Name Synonyms: bog 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: 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 Hosackia pinnata and H. gracilis have well-developed stipules and usually have 5 or more leaflets so they are not trefoils.
Species Group: Vascular Plant
Species Code: HOSAPIN
Kingdom Phylum Class Order Family
Plantae Anthophyta Dicotyledoneae Fabales Fabaceae
   
Conservation Status / Legal Designation
Global Status: G4G5 (Mar 2001)
Provincial Status: S2? (Apr 2019)
BC List: Red
Provincial FRPA list:   
Provincial Wildlife Act:
COSEWIC Status: Endangered (May 2004)
SARA Schedule: 1  -  Endangered (Jul 2005)
General Status Canada: 1 - At Risk (2010)
   
Ecology & Life History
General Description:
Technical Description:
Subspecies Comments: There are no subspecies of Lotus pinnatus recognized in BC (Douglas et al. 1999).
Identification Comments: Lotus pinnatus is a low-growing, perenniel herb from a thick taproot and short rhizome with many erect to spreading stems, from 15 to 60 cm long. The leaves are 4 to 8 cm long, alternate, stalked and pinnately compund with 5 to 9 elliptic, oblong or narrowly egg-shaped leaflets. The stipules are membranous, obovate and 3 to 10 mm long. The inflorescence is a compact, stalked, axillary umbel of 3 to 12 pea-like flowers and the umbel stalks are bractless or with a single membranous bract. The corollas are from 10 to 15 mm long with a yellow banner and keel and creamy white wings. The keel petals are fused along one edge that is elongated into a well-defined beak towards the outside of inflorescence. The calyx is tubular and 4 to 8 mm long with triangular-lanceolate teeth that are all much shorter than the tube. The linear seed pods range from 3 to 6 cm in length and contain 5 to 20 glabrous seeds (Douglas et al. 1999).
Similar Species: In the field, Vicia species may be confused with L. pinnatus as they are often present in similar habitats, but the leaves in Vicia spp. are smaller in size than those of L. pinnatus and the terminal leaflet in Vicia spp. is represented by a tendril. Lotus formosissimus looks very similar to L. pinnatus except the wing petals of L. formosissimus are pinkish-purple, while those of L. pinnatus are cream-colored. Though a trifoliate bract usually subtends the flowers of L. formosissimus, bracts were sometimes absent in the field specimens or only a unifoliate bract was present (Ryan and Douglas 1994). Although L. pinnatus and L. formosissimus could be confused if the plants are immature or not in flower, the two species do not overlap in their distribution in British Columbia (Donovan, 2004).
Provincial Reproduction Comments: Like other perennial species in the genus Lotus, Zandstra and Grant (1968) suggested that the flowers of Lotus pinnatus require cross-pollination to set viable seed. Though specific pollinators have not yet been reported in the literature for L. pinnatus, honey bees, bumblebees and leaf-cutting bees have been described as effective pollinators of the related perennial species, L. corniculatus. It is not clear how frequently pollen is exchanged in L. pinnatus and over what distances but Morse (1958) reported that 12 to 15 visits per flower were required for maximum seed set in L. corniculatus. The Lotus flower is constructed so that the anthers of the longer fused stamens are enclosed within the beak of the keel petals. Pollen is released into the beak of the keel petals prior to flowering. Pressure exerted by visiting insects on the keel causes the five dilated staminate filaments to act as a piston, pushing pollen out of the tip onto the ventral surface of the insect's thorax. In L. corniculatus, the protrusion of the pistil beyond the stamens places the pistil in closer contact with pollen deposited on the body of visiting insects than with the pollen of its own flower and is believed to be an adaptation to ensure cross-pollination (Morse, 1958). Given the bright yellow appearance of the flower and the wide keel that serves as a suitable landing platform, flowers of L. pinnatus appear to be adapted to bee pollination (Donovan, 2003).
Provincial Ecology Comments: Lotus pinnatus is most commonly associated with Mimulus guttatus, Plectritis congesta, Triteleia hyacinthina, Montia parvifolia, Plagiobothrys scouleri and Veronica beccabunga ssp. americana. Stands of Pseudotsuga menziesii and dense thickets of Rosa nutkana, Holodiscus discolor, Physocarpus capitatus and Salix species exist on the margin of some seepages but L. pinnatus does not occur in the shaded understory of these sites, suggesting that the species is shade-intolerant. Prolonged moisture, edge habitat along streams and meadows and shallow soils derived from sedimentary rock are key habitat components. The soil at Harewood Plains, site of the largest population, is a Lithic Dystric Brunisol overlying gently sloping sandstone or conglomerate bedrock of the Nanaimo Formation.
Habitats:
(Type / Subtype / Dependence) 		Grassland/Shrub / Meadow / Facultative - frequent use
Other Unique Habitats / Vernal Pools/Seasonal Seeps / Facultative - frequent use
Riparian / Riparian Herbaceous / Facultative - occasional use
Provincial Habitat Comments: British Columbia populations of Hosackia pinnata occur in open, springy meadows, along the margins of creeks, in wet ditches or in seepages, where underground water comes to the surface. In all cases, the soils are shallow (< 15 cm), over gently sloping sandstone or conglomerate bedrock with abundant moisture during the growing and blooming period. Prolonged moisture, edge habitat along streams and meadows and shallow soils derived from sedimentary rock are key habitat components. Other factors, such as slope and aspect are variable and do not appear to be critical in defining suitable habitat. In BC, the elevation for this species ranges between 40 m and 150 m (Donovan, 2003).
Provincial Phenology:
(1st half of month/
2nd half of month)		 Feb: / Germinating
Mar: Germinating / Germinating
Apr: Vegetative / Vegetative
May: Flowering / Flowering
Jun: Flowering / Flowering
Jul: Fruiting / Fruiting
Aug: Fruiting /
Provincial Phenology Comments: Lotus pinnatus germinates and begins growth in late winter - early spring as a result of increasing daylength and the warm, moist conditions found at this time of the year. Since the surrounding vegetation, especially grasses, are shorter during this period, the herbs benefit from greater light levels and space to grow. Each plant sends up from 3 to 6 shoots, on average, from its taproot and vegetative growth occurs in early spring. Though the specific timing of events will depend on local habitat conditions and may vary from year to year, flowering generally occurs between May and the end of June. The umbellate inflorescences are produced sequentially throughout the growing season. Fruiting begins before summer moisture deficits reduce the plant's productivity and each ramet is likely to have flower buds, flowers and immature fruits in various stages of development, at any time during the growing season. During July, when drought conditions are prevalent, seed maturation and dispersal begins, followed by die-back of the stems to the rootstock. The plants become senescent and remain dormant until the following year (Donovan, 2003).
Elevation (m) (min / max): Provincial:  40 / 50
Known Pests:
Pollen Vector:
Pollinator:
Dispersal:
   
 
Provincial Inventory
Inventory Priority: C - Moderate
Ownership of occurrences (Known locations): Mostly private
Inventory Need: A detailed inventory and mapping of suitable habitats (e.g. open, springy meadows, creek margins, wet ditches and seepages), especially on previously unsurveyed private lands, within the known range of the species is recommended.

To encourage the support of monitoring and research projects, protocols should be developed in consultation with involved land owners and managers. Monitoring results should also be regularly forwarded to relevant stakeholders and agencies (Miller, 2005)
Inventory Comments: There are seven known populations of L. pinnatus in Canada. Historic populations at two other sites could not be relocated in 2003 and are likely extirpated (Donovan, 2004).
 
Economic Attributes
Provincial Economic Comments: Lotus pinnatus is not currently collected for any purpose in Canada. Seeds can be purchased online from an American seed company presumably for horticultural use or for the restoration of disturbed sites. The species could also be tested for medicinal compounds (Donovan, 2003).
 
Distribution
Endemic: N
Disjunct, more common elsewhere: Y
Peripheral, major distribution elsewhere: Y
 
Authors / Contributors
Global Information Author:
Last Updated:
Provincial Information Author: Donovan, M.
Last Updated: Nov 21, 2005
Last Literature Search:
   
References and Related Literature
B.C. Ministry of Environment. Recovery Planning in BC. B.C. Minist. Environ. Victoria, BC.
COSEWIC. 2004s. COSEWIC assessment and status report on the bog bird's-foot trefoil Lotus pinnatus in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. vi + 33 pp.
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.
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.
Maslovat, C. 2009. Guidelines for Translocation of Plant Species at Risk in British Columbia. B.C. Minist. of Environ. Victoria, BC.
Morse, R.A. 1958. The pollination of birdsfoot trefoil (Lotus corniculatus L.) in New York State. Pp. 951-953 in J.W. Arnold, ed. Proc. 10th Int. Congr. Entomol. Montreal, Canada. June 1958. Int. Congr. Entomol., Montreal, PQ.
Parks Canada Agency. 2006. Recovery Strategy for Multi-species at Risk in Vernal Pools and Other Ephemeral Wet Areas in Garry Oak and Associated Ecosystems in Canada. Species at Risk Act Recovery Strategy Series. Ottawa: Parks Canada Agency. 73 pp.
 

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 pinnata. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Nov 8, 2024).