Identity
Unique IDELEMENT_GLOBAL.2.157386
Element CodePDPLM02090
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderSolanales
FamilyPolemoniaceae
GenusCollomia
Other Common NamesCollomia délicat (FR)
Concept ReferenceKartesz, 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.
Conservation Status
Rank Method Rank calculation - Biotics v2
Review Date2025-02-06
Change Date2025-02-06
Edition Date2025-02-24
Edition AuthorsEberly (2025)
Threat ImpactUnknown
Range Extent200,000-2,500,000 square km (about 80,000-1,000,000 square miles)
Number of Occurrences21 - 300
Rank ReasonsCollomia tenella is an annual herb that occurs in western North America from southwestern British Columbia (Canada) south to California, Nevada, Utah, and Colorado (United States). This species is uncommon or rare in some areas but it is likely underreported as a small, inconspicuous annual. The northernmost occurrence in British Columbia has multiple threats, but threats are not known for the majority of its range. Many occurrences are reported from public lands in the United States.
Range Extent CommentsCollomia 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).
Occurrences CommentsBy applying a 1 km separation distance to herbarium specimens, photo-based observations, and NatureServe Network occurrence data documented between 1984 and 2025, it is estimated that there are more around 72 occurrences rangewide (GBIF 2025, iNaturalist 2025, NatureServe 2025, SEINet 2025). This species has a spotty distribution over a large range, resulting in geographically, and possibly genetically, isolated occurrences. This annual may not germinate in years with unfavorable conditions, and thus it it may be difficult to detect in a given year. In addition, it is a small plant that could be easily overlooked. Given these considerations and the number of specimens that are not georeferenced, their are likely more than 72 or even 80 occurrences. Welsh et al. (2015) note "This is a slender-leaved dwarf plant that is easily overlooked. It is likely more common and possibly more widely distributed than the few records indicate."
Threat Impact CommentsThis species is potentially threatened by exotic species, including Linaria genistifolia and Bromus tectorum. The northernmost and only occurrence in British Columbia is on a privately owned Agricultural Land Reserve, where recreational off-road vehicles, drilling for coalbed methane gas, sand removal to support road maintenance, and development may threaten the species (Douglas and Penny 2006). This occurrence is isolated and may be at risk of inbreeding depression, which may be an issue for isolated occurrences in other parts of its range (COSEWIC 2003).