Phaeocollybia fallax was described from western North America, with the Type collection made on the Olympic Peninsula in Washington, USA (Smith 1957).
Phaeocollybia fallax is a widespread species in western North America, but with a disjunct distribution. Currently known from ~100 locations (Norvell & Exeter 2009, Mycoportal 2021), however, some of these records are historic, and many of these sites have been subjected to repeated timber harvest.
Most collections come from mid to late seral stage and old growth forests; this species appears to be able to colonize forest at a younger age than most Phaeocollyia species. Based on the number of known locations, and recent reports, this species appears to be locally common where suitable habitat exist, but overall habitat has, and continues to decline. However, it may be common enough, and have enough of a habitat range to qualify as a Least Concern (LC) listing.
Widespread in western North America, from the Santa Cruz Mountains in the southern portion of the range, north through coast and Coast Range forests into southern British Columbia, with scattered sites in the Cascade Range in Oregon and Washington, and a single record from Idaho (Mycoportal 2021).
Population is widespread, and appears stable in suitable habitat. Currently known from ~100 locations (although about a quarter of these are historic). Although it has a preference for late seral stage and old growth forests, it is not restricted to such sites, and appears to be able to colonize forest at a younger age than most Phaeocollyia species. Based on recent reports, this species appears to be locally common, and stable in protected old growth habitats, but absent or declining from unprotected sites.
Population Trend: Uncertain
Ectomycorrhizal with conifers and possibly Tanoak; it has a preference for late seral stage and old growth forests. Fruit bodies are usually scattered or in small groups, and often are intermingles with other Phaeocollybia species. They typically occur in undisturbed forests, in areas with thick duff or moss. Fruiting in fall and early winter.
This is a ectomycorrhizal fungus species dependent on living host trees for viability. The major threat to this species and its co-occurring co-generic brethren is habitat destruction, via the logging of old-growth forests to which this species has a preference for. The extent of old growth forest in the Pacific Northwest of North America has declined 90% in the last century (Society of American Foresters 1984, Haynes 1986).
Climate change and droughts, along with forest management practices has made western forests highly susceptible to stand replacing forest fires. Fire is big threat to this species’ populations. A stand replacing fire could severely degrade and/or diminish its current range. Logging and machine clearing of understory vegetation should be limited in mature and old growth forest in areas where this species might occur.
This species is included on the United States Forest Service Northwest Forest Plan Survey and Manage list of rare/old growth forests dependent fungi, and has been actively surveyed for since the late 1990’s.
Continued surveys for existing populations. A better understanding of habitat restraints and requirements; is it restricted to old growth
Castellano, M.A., Smith, J.E., O’Dell, T., Cázares, E. and Nugent, S. 1999. Handbook to Strategy 1 Fungal Species in the Northwest Forest Plan. U. S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: Portland, OR. 195 p.
Haynes, T.W. 1986. Inventory and value of old-growth in the Douglas-fir region. PNW-RN 437. U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Portland, OR.
MyCoPortal. 2021. http://mycoportal.org/portal/index.php. Accessed on February 12.
Norvell, L. and Exeter, R.L. 2009. Phaeocollybia of Pacific Northwest North America. US Department of Interior, BLM: Salem, OR. 229 p.
Siegel, N. and Schwarz, C. 2016. Mushrooms of the Redwood Coast. Ten Speed Press: Berkeley, CA. 601 p.
Smith, A.H. 1957. A contribution toward a monograph of Phaeocollybia. Brittonia 9: 195-217.
Society of American Foresters. 1984. Scheduling the harvest of old growth : Old-growth forests in the Pacific Northwest : a position of the Society of American Foresters and Report of the SAF Task Force on Scheduling the Harvest of Old-Growth Timber. Bethesda, MD.