BC Conservation Data Centre: Species Summary
Calochortus lyallii
Lyall's mariposa lily
| Scientific Name: | Calochortus lyallii Baker | ||||||||||
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| English Name: | Lyall's mariposa lily | ||||||||||
| 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: | CALOLYA | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G3G4 (Aug 2016) | ||||||||||
| Provincial Status: | S3 (Apr 2019) | ||||||||||
| BC List: | Blue | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Special Concern (May 2011) | ||||||||||
| SARA Schedule: | 1 - Special Concern | ||||||||||
| General Status Canada: | 1 - At Risk (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | There are no described subspecies. | ||||||||||
| Identification Comments: | This is a long-lived, bulbous, perennial herb. Leaves are narrow and grass-like, gray-green, distributed along a flowering stem, and wider in non-flowering plants. Flowers number 1-10 per plant and are 3-5 cm across. There are 3 petals and sepals. The petals are white with purplish crescent-shaped markings near the base and are sparsely hairy on the inner surface (Douglas et al 2001; COSEWIC 2001b). | ||||||||||
| Similar Species: | The only look-alike is the white-flowered Calochortus apiculatus, which is larger and lacks the moon-shaped spot at the base of the petal. C. apiculatus also has hanging capsules, while C. lyallii capsules are upright. However, C. apiculatus has apparently not been found in sympatry with Canadian (BC) populations of C. lyallii (Miller et al 2004). | ||||||||||
| Provincial Reproduction Comments: |
Reproduction appears to be by seed with an average of 20 seeds per fruiting capsule. Seeds are gravity dispersed, and most seedlings establish close to parent plants (Miller 2004). Individuals of the long-lived Lyall's Mariposa Lily often undergo marked changes in size and demographic stage from one year to the next. The relative proportion of reproductive vs. non-reproductive individuals in the population also varies from year to year, since different individuals may progress through the life cycle at different rates and may respond in different ways to prevailing environmental conditions. Between 1997 and 2007, for example, the ratio of mature flowering to sterile stems inside permanent demographic plots at subpopulation 1a decreased from 3.0 to 0.81. In subpopulation 2a and 3a, this ratio declined from 1.5 to 0.36 and from 1.9 to 0.51, respectively. |
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| Provincial Ecology Comments: | In BC, Calochortus lyallii occurs in variable population sizes that appear to be positively correlated with soil depth. It has a relatively stable life history, which may buffer it from stochastic environmental variation. Prolonged bulb dormancy appears to be common, and dormancy up to four years has been recorded (Miller et al. 2004). This has important implications for inventory and population estimates because the number of plants that are visible at a given time will not reflect the total population. Fruit set seems to be resource- or pollen-limited, and has been found to be positively correlated with previous year temperature and precipitation. Fruit set is depressed by insect grazing, rodent predation on bulbs, and mechanical damage by large mammals. Low fruit set also appears to be primarily related to premature abortion of buds and flowers (Miller 2004; Miller et al. 2004; Miller et al 2007). | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Forest / Conifer Forest - Dry / Obligate
Grassland/Shrub / Meadow / Facultative - frequent use Grassland/Shrub / Sagebrush Steppe / Obligate |
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| Global Habitat Comments: | Open Douglas fir and pine forests and slopes, usually in natural openings with grass-forb meadow vegetation. Occurs on predominantly dry, occasionally mesic sites, usually with well-drained, shallow soil. In steppe and montane zones (moderate elevations), 300 - 1500 m. | ||||||||||
| Provincial Habitat Comments: | Calochortus lyallii inhabits natural openings in Douglas-fir (Pseudotsuga menziesii var. glauca) forests on all aspects at elevations ranging from 900 to 1300 metres. These sites are mainly grass-forb meadows that range from dry to mesic, occur on 0-40% slopes, and contain a diverse plant community dominated by two species of bunchgrass: bluebunch wheatgrass (Pseudoroegneria spicata) and Idaho fescue (Festuca idahoensis). Shrub cover is generally sparse but includes birch-leaved spirea (Spiraea betulifolia), squaw current (Ribes cereum), and saskatoon (Amelanchier alnifolia). A few invading/residual Douglas-fir trees are also present at most of the sites (Miller and Douglas 1998; Miller and Douglas 2000; COSEWIC 2001b; Douglas et al 2002). | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
Apr: Vegetative, Germinating / Vegetative, Germinating
May: Vegetative / Vegetative Jun: Vegetative, Flowering / Flowering Jul: Fruiting / Fruiting Aug: Fruiting / Fruiting |
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| Provincial Phenology Comments: | Lyall's mariposa lily has a complex life cycle composed of the following states: seeds, seedlings, juveniles or sub-adults, flowering plants, vegetative (non-flowering) individuals, and dormant bulbs. Transitions among these different states is not necessarily a linear process, as stasis and retrogression are both common (Miller 2000; Miller 2004). Prolonged bulb dormancy is a common phenomenon in this species (Miller et al 2004). Vegetative shoots and seedlings both emerge in April, usually before the last patches of snow have completely melted (Miller 2005). The seedlings remain green for about three weeks before dying back to the new bulb and entering dormancy until the following year. Flowering of established plants commences in early June, with seed set occurring in July and August (Miller 2004). | ||||||||||
| Elevation (m) (min / max): | Provincial: 900 / 1300 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | A - Highest | ||||||||||
| Ownership of occurrences (Known locations): | Mostly state/provincial government | ||||||||||
| Inventory Need: |
The vicinity of the known locations in the South Okanagan Grasslands Protected Area has been intensively searched, but extensive areas of suitable habitat remain to be surveyed on Mt. Kobau to the north, and on Chopaka and Snowy Mountains to the west (M. Miller, pers. comm. 2007). |
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| Inventory Comments: | A detailed inventory of the South Okanagan Grasslands Protected Area was conducted by Ministry of Environment staff in 2007, resulting in the discovery of 2 new subpopulations, and updated information on the 10 previously known subpopulations (Klym et al 2007). The methodology used in this inventory has been incorporated into the stewardship plan for Lyall's Mariposa Lily in the South Okanagan Grasslands Protected Area (Dyer et al 2008). This plan establishes a schedule for inventory and monitoring, and stipulates that all staff working in the SOGPA will be trained to recognize Calochortus lyallii in order to facilitate opportunistic inventory for new sites. | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | The species has no present economic importance. | ||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | Far southern British Columbia (close to the U.S. border) southward along the eastern front of the Cascade Mountains to Yakima County, Washington. Occasionally east of the Columbia River (e.g. on Badger Mountain, WA). Range extent (estimated from Ownbey 1940) appears to be approximately 13,000 square km. | ||||||||||
| Disjunct, more common elsewhere: | N | ||||||||||
| Peripheral, major distribution elsewhere: | Y | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | |||||||||||
| Last Updated: | |||||||||||
| Provincial Information Author: | J.L. Penny and N.G. Kondla | ||||||||||
| Last Updated: | Aug 22, 2008 | ||||||||||
| 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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COSEWIC. 2001b. COSEWIC assessment and status report on the the Lyall's mariposa lily Calochortus lyallii in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 24 pp. |
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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. 2001. Illustrated Flora of British Columbia, Vol. 6, Monocotyledons (Acoraceae through Najadaceae). B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria, BC. 361pp. |
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Douglas, G.W., G.B. Straley, and D. Meidinger (eds). 1994. The Vascular Plants of British Columbia: Part 4 - Monocotyledons. Ministry of Forests Research Program, Victoria, British Columbia. 257 pp. |
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Dyer, O., Gunoff, S. Bunge and C. Klym. 2008. Stewardship plan for the Lyall's Mariposa Lily in the South Okanagan Grasslands Protected Area: 2008 to 2012. Working Report. Minist. of Environ. Penticton. 8 pp. |
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Flora of North America Editorial Committee (FNA). 2002a. Flora of North America north of Mexico. Vol. 26. Magnoliophyta: Liliidae: Liliales and Orchidales. Oxford Univ. Press, New York. xxvi + 723 pp. |
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Hitchcock, C.L., A. Cronquist, M. Ownbey, and J.W. Thompson. 1969. Vascular plants of the Pacific Northwest. Part 1: Vascular cryptogams, gymnosperms, and monocotyledons. Univ. Washington Press, Seattle. 914 pp. |
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Klym, C., S. Bunge and O. Dyer. 2007. Lyall's Mariposa Lily inventory, monitoring and stewardship: 2005-2007. Working Report. BC Ministry of Environment. Penticton. 7 pp. |
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Miller, M. T. and G. A. Allen. 2001. Lyall's Mariposa Lily (Calchortus lyallii): Management recommendations for B.C. populations. Online. Available: http://web.uvic.ca/~herb/caly.htm (Accessed 2008). |
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Miller, M., and G. W. Douglas. 1998. Status of Lyall's Mariposa Lily, Calochortus lyallii Baker, in British Columbia. Wildl. Bull. No. ?, B.C. Minist. Environ., Lands and Parks, Wildl. Branch, Victoria. |
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Miller, M., and G.W. Douglas. 2000. Status Report on Lyall's Mariposa Lily, Calochortus lyallii, in Canada. Unpubl. rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 32pp. |
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Miller, M.T. 2000. Demographic Performance and Microhabitat Variability in a Threatened Species. P. 443 in L.M. Darling, ed. 2000. Proc. Conf. on the Biology and Manage. Species and Habitats at Risk, Kamloops, B.C., 15-19 Feb., 1999. Vol. 1; B.C. Minist. Environ., Lands and Parks, Victoria, BC, and Univ. College of the Cariboo, Kamloops, BC. 490pp. |
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Miller, M.T. 2004. Demographic perspectives on the rarity and persistence of two mariposa lilies (Calochortus) from southern British Columbia. PhD. dissertation, Dep. Biol., Univ. of Victoria, Victoria, BC. |
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Miller, M.T. 2005. Draft National Recovery Strategy for Lyall's mariposa lily (Calochortus lyallii). Prepared for the Southern Interior Rare Plants Recovery Implementation Group. Recovery of Natl. Endangered Wildl. Comm., Ottawa, ON. 37 pp. |
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Miller, M.T., and G.W. Douglas. 1999. Status of Lyall's Mariposa Lily, Calochortus lyallii (Liliaceae), in British Columbia. Can. Field-Nat. 113(4):652-658. |
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Miller, M.T., and G.W. Douglas. 1999b. Status of Lyall's Mariposa Lily, Calochortus lyallii (Liliaceae), in Canada. Can. Field-Nat. 113:652-658. |
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Miller, M.T., G.A. Allen, and J.A. Antos. 2004. Dormancy and flowering in two mariposa lilies (Calochortus) with contrasting distribution patterns. Can. J. Bot 82:1790-1799. |
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Miller, M.T., J.A. Antos, and G.A. Allen. 2007. Demographic differences between two sympatric species of Calochortus (mariposa lily) as revealed by matrix analysis. Plant Ecology 191:265-268. |
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Mosquin, D. 2007. Botany Photo of the Day: Calochortus lyallii. Posted on Botany Photo of the Day, a daily photo weblog run by the staff and researchers of UBC Botanical Garden. 18 July 2007. Online. Available: http://www.ubcbotanicalgarden.org/potd/2007/07/calochortus_lyallii.php (Accessed 2008). |
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Ownbey, M. 1940. A monograph of the genus Calochortus. Annals of the Missouri Botanical Garden 27(4): 371-560. |
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Southern Interior Rare Plants Recovery Implementation Group. 2008c. Recovery strategy for Lyall's mariposa lily (Calochortus lyallii) in British Columbia. Prepared for the B.C. Minist. of Environ., Victoria, BC. 17 pp. + annex 9 pp. |
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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: Calochortus lyallii. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Jun 8, 2026).