BC Conservation Data Centre: Species Summary
Collomia tenella
slender collomia
| Scientific Name: | Collomia tenella Gray | ||||||||||
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| English Name: | slender collomia | ||||||||||
| 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: | COLLTEE | ||||||||||
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| Conservation Status / Legal Designation | |||||||||||
| Global Status: | G4 (Feb 2025) | ||||||||||
| Provincial Status: | S1S2 (Apr 2019) | ||||||||||
| BC List: | Red | ||||||||||
| Provincial FRPA list: | |||||||||||
| Provincial Wildlife Act: | |||||||||||
| COSEWIC Status: | Endangered (Nov 2003) | ||||||||||
| SARA Schedule: | 1 - Endangered (Jul 2005) | ||||||||||
| General Status Canada: | 1 - At Risk (2010) | ||||||||||
| Ecology & Life History | |||||||||||
| General Description: | |||||||||||
| Technical Description: | |||||||||||
| Subspecies Comments: | No subspecies are known to occur in B.C. | ||||||||||
| Identification Comments: | Collomia tenella can be distinguished from other Collomia species in the province by its entire leaves, one-seeded capsules, branched stems with spreading branches, and single or paired flowers growing at the ends and forks of branches (Douglas et al. 1999). | ||||||||||
| Similar Species: | No known look-alikes occur in B.C. | ||||||||||
| Global Reproduction Comments: | The seeds of this plant are sticky when wet, which has been hypothesized to facilitate animal dispersal or to adhere the seeds to soil close to the parent plant, ensuring the seeds sprout in favorable habitat (Hsiao and Chuang 1981). | ||||||||||
| Provincial Reproduction Comments: | Collomia tenella has an annual life cycle. Like other annual members of the genus, the species may be self-compatible and self-pollinating. Its seeds are sticky when moist, and animals are possible seed dispersal agents (Douglas and Penny 2003b). | ||||||||||
| Provincial Ecology Comments: | No information is available on the ecology of Collomia tenella at the subnational level. | ||||||||||
| Habitats: (Type / Subtype / Dependence) |
Forest / Conifer Forest - Dry / Facultative - frequent use
Grassland/Shrub / Sagebrush Steppe / Facultative - frequent use Rock/Sparsely Vegetated Rock / Rock/Sparsely Vegetated Rock / Facultative - frequent use |
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| Global Habitat Comments: | This species grows in dry, open areas in sagebrush, pinyon-juniper, mountain brush, aspen, and spruce-fir communities (Welsh et al. 2015, Jepson Flora Project 2025). It is often reported from along roadsides and trails (SEINet 2025). | ||||||||||
| Provincial Habitat Comments: | The B.C. population of Collomia tenella is located within the Okanagan Very Dry Hot Interior Douglas-fir (IDFxh1) biogeoclimatic unit (Lloyd et al. 1990). Climatic conditions in the IDFxh1 are continental and characterized by hot, dry summers, a fairly long growing season, and cool winters. Douglas and Penny (2003b) describe the habitat as "eroded, steeply-sloped, southeast-facing sections of a sandy ridge. The sandy ridge, formed by fluvial processes during the last glaciation, consists of fine-textured sands. The eroded sections of the slopes are sparsely vegetated with about 20% cover." The vegetation includes the shrub Amelanchier alnifolia as well as a variety of herbs: Balsamorhiza sagittata, Astragalus miser, Collomia linearis, Phacelia linearis, Lupinus sericeus, Linaria genistifolia ssp. dalmatica, Bromus tectorum, and Pseudoroegneria spicata. Scattered Pseudotsuga menziesii and Pinus ponderosa trees occur on the ridge (Douglas and Penny 2003b). | ||||||||||
| Provincial Phenology: (1st half of month/ 2nd half of month) |
Jun: Flowering / Flowering
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| Provincial Phenology Comments: | In B.C., Collomia tenella has been observed flowering in June. The exact phenology of the species' germination, vegetative, flowering, and fruiting stages is unknown. | ||||||||||
| Elevation (m) (min / max): | Provincial: 269 / 269 | ||||||||||
| Known Pests: | |||||||||||
| Pollen Vector: | |||||||||||
| Pollinator: | |||||||||||
| Dispersal: | |||||||||||
| Provincial Inventory | |||||||||||
| Inventory Priority: | B - Strong | ||||||||||
| Ownership of occurrences (Known locations): | Mostly private | ||||||||||
| Inventory Need: | Monitoring of all sites containing Collomia tenella is recommended since large fluctuations in population size can occur from year to year, which makes it difficult to assess trends based on population numbers in any given year. Habitat mapping is needed to identify areas of good potential habitat that have not yet been surveyed. Inventories should be conducted by a qualified botanist at the appropriate time of year. | ||||||||||
| Inventory Comments: | A national survey for Collomia tenella was conducted in 2003, and the results were included in the COSEWIC status report (Douglas and Penny 2003b). Additionally, in 2002 and 2003, Frank Lomer searched specifically for new sites near the known location in the Princeton area. He surveyed the east side of the Similkameen River opposite the known site and along the U.S. border near Grand Forks, Anarchist Mountain, and Midway, but he did not find any new sites (Douglas and Penny 2003b). | ||||||||||
| Economic Attributes | |||||||||||
| Provincial Economic Comments: | Collomia tenella has no known economic attributes in B.C. | ||||||||||
| Distribution | |||||||||||
| Endemic: | N | ||||||||||
| Global Range Comment: | Collomia tenella occurs in western North America from southwestern British Columbia in Canada Canada and south through the western United States in northern California, northwestern Colorado, Idaho, eastern Oregon, northern and western Utah, Central Washington, and western Wyoming. Range extent was estimated using herbarium specimens, photo-based observations, and NatureServe Network occurrence data collected between 1984 and 2025 (GBIF 2025, iNaturalist 2025, NatureServe 2025, SEINet 2025). | ||||||||||
| Disjunct, more common elsewhere: | Y | ||||||||||
| Peripheral, major distribution elsewhere: | Y | ||||||||||
| Authors / Contributors | |||||||||||
| Global Information Author: | Enns, A. | ||||||||||
| Last Updated: | Jul 18, 2018 | ||||||||||
| Provincial Information Author: | Barton, K. | ||||||||||
| Last Updated: | Mar 24, 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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Committee on the Status of Endangered Wildlife in Canada (COSEWIC). 2003. COSEWIC assessment and status report on the slender collomia Collomia tenella in Canada. Committee on the Status of Endangered Wildlife in Canada. Ottawa. vi + 14 pp. |
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COSEWIC. 2003p. COSEWIC assessment and status report on the slender collomia Collomia tenella in Canada. Comm. on the Status of Endangered Wildl. in Can. Ottawa. vi + 14 pp. |
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Douglas, G.W. and J.L. Penny. 2003b. Status Report on Slender Collomia, Collomia tenella, in Canada. Unpubl. rep. submitted to the Comm. on the Status of Endangered Wildl. in Can. Ottawa. 15pp. |
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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. 4, Dicotyledons (Orobanchaceae through Rubiaceae). B.C. Minist. Environ., Lands and Parks, and B.C. Minist. For., Victoria. 427pp. |
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Douglas, G.W., F. Lomer, and H. Roemer. 1998. New or Rediscovered Native Vascular Plant Species in British Columbia. Can. Field-Nat. 112(2):276-279. |
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Hickman, J. C., ed. 1993. The Jepson manual: Higher plants of California. University of California Press, Berkeley, CA. 1400 pp. |
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Hsiao, Y.-C., and T.I. Chuang. 1981. Seed-Coat Morphology and Anatomy in Collomia (Polemoniaceae). American Journal of Botany 68:1155-1164. https://doi.org/10.1002/j.1537-2197.1981.tb07821.x |
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Southern Interior Rare Plants Recovery Implementation Group. 2008b. Multi-species recovery strategy for the Princeton Landscape, including dwarf woolly-heads (Psilocarphus brevissimus var. brevissimus), slender collomia (Collomia tenella), and stoloniferous pussytoes (Antennaria flagellaris) in British Columbia. Prepared for the B.C. Ministry of Environment, Victoria, BC. 28 pp. |
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Welsh, S.L., N.D. Atwood, S. Goodrich, and L.C. Higgins. (Eds). 2015. A Utah flora, fifth edition, revised 2015. Monte L. Bean Life Science Museum, Provo, Utah. 987 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. 2018. Species Summary: Collomia tenella. B.C. Minist. of Environment. Available: https://a100.gov.bc.ca/pub/eswp/ (accessed Sep 25, 2025).