Calochortus lyallii

Known from five occurrences in south-central British Columbia; more common in Washington, where the range extends southward along the eastern front of the Cascades to Yakima County. Some populations in both BC and WA are relatively large and dense. BC populations have been intensively studied and several are believed to have good probability of persistence. Threats include inappropriate reforesting of the species' naturally open habitat following fires or logging, competition with invasive species, and livestock grazing.

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.

There are 5 occurrences in British Columbia, which include 14 subpopulations or colonies (BC CDC 2007). The species is more common in Washington, where occurrences are not mapped individually. Approximately 52 Washington collections are represented by those listed in Ownbey (1940) plus collections dated 1939 and later in the Burke Museum herbarium (WTU). This is a very approximate idea of the number of occurrences, as collections may not have been made from all known populations, and more than one collection may have been made from the same occurrence (although obvious duplicates were removed).

Inappropriate reforestation practices after fires or logging operations (e.g. planting tree seedlings in natural meadow opening areas) can threaten the naturally open habitat required by the species. Competition with weedy invasive species is also a threat; this threat is expected to increase in the future, at least in BC, as additional propagules of weeds come in contact with C. lyallii occurrences via roads, livestock, etc. Grazing by livestock and deer (including trampling impacts) is a concern, although populations appear to have persisted despite long-term livestock grazing in some areas. Logging may be a threat in Washington, but is no longer a major threat in BC (BC CDC 2007).