Described from Oregon, USA (Smith & Hesler 1962).
Two varieties were described; L. fallax var. fallax and L. fallax var. concolor on basis of marginate gill edges; little else separates them (Hesler & Smith 1979, Methven 1997).
Genetic studies have showed that there are two species being called Lactarius fallax in the Pacific Northwest.
“The western North American L. fallax is a paraphyletic species comprising at least two species. The two clades recovered in the analysis cannot be distinguished microscopically. Both clades contain a specimen with pigmented lamella edges and a specimen without pigmentation in the lamella edge” (Stubbe & Verbeken 2012).
More work is needed to delimit species in this complex.
Lactarius picinus var. maritimus A.H. Sm. & Hesler and L. lignyotus var. americanus are synonyms (Hesler & Smith 1979).
Lactarius fallax is a common species on the Pacific Coast; from Northern California into Alaska, and across the Pacific Northwest mountains.
However, genetic studies (Stubbe & Verbeken 2012) showed that there are two species being called Lactarius fallax in western North America. Until species parameters can be delimited, I recommend listing as Data Deficient (DD).
The Pacific Coast of North America, from northern California into southeast Alaska, the Cascade range of northern Oregon into British Columbia, Canada, east to Idaho, USA.
Lactarius fallax is a common species with a widespread population; occurring in young to mature conifer forests in coastal northern California, Pacific Northwest and Alaska. No decline has been recorded.
Population Trend: Stable
Ectomycorrhizal with Sitka spruce (Picea sitchensis), and other conifers, likely fir (Abies spp.), and hemlock (Tsuga spp.). Very common in coastal forests, occasional in montane forests.
No threats have been identified with regards to this species.
No specific conservation actions is needed with regards to this species.
Modern taxonomic work and genetic sequencing to delimit species parameters.
This is an edible species (Siegel & Schwarz 2016), but not often collected.
Hesler, L.R. and Smith, A.H. 1979. North American Species of Lactarius. University of Michigan Press: Ann Arbor, MI. 841 p.
Methven, A.S. 1997. The Agaricales (Gilled Fungi) of California. 10. Russulaceae II. Lactarius. Mad River Press: Eureka, CA. 79 p.
Siegel, N. and Schwarz, C. 2016. Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.
Smith, A.H. and Hesler, L.R. 1962. Studies on Lactarius—III. The North American Species of Section Plinthogali. Brittonia 14: 369-440.
Stubbe, D., and Verbeken, A. 2012. Lactarius subg. Plinthogalus: the European taxa and American varieties of L. lignyotus re-evaluated. Mycologia, 104(6), 1490–1501.