Described from a collection made near McCall, Idaho, USA (Smith & Zeller 1966).
The name has been applied to eastern North American and European collections, all of which need to be critically examined, as they likely represent a distinct species (or are introductions from western North America).
Many Rhizopogon lack distinctive morphological characters, and can only be reliably identified with genetic sequences.
Rhizopogon abietis is a hypogeous fungus with a rubbery texture, yellow to brown-yellow young peridium, which stains pink to vinaceous when bruised, aging dark olive to brown with yellow to red-brown blotches, a whitish to dark olive gleba and fusoid to subcylindrical spores measuring 7.5–13 x 3–5 (6) μm (Siegel et al. 2019)
Currently known from 17 locations in western North America, over a widespread area. The name has been applied to eastern North American and European collections.
We could either list as Data Deficient (DD) based on the taxonomic issues, or make an assessment based on the western collections only.
In western North America, this species occurs from the Siskiyou Mountains in northern California, through the Cascade Range in the Pacific Northwest, east into the Rocky Mountains in Idaho; this likely represents the native range of Rhizopogon abietis. Reported from eastern North America, from Ontario, Canada south into Tennessee and Virginia, USA; (Siegel et al. 2019, Mycoportal 2021), these records should be further investigated, as they likely pertain to a distinct species.
Also reported from Mexico, Sweden, Denmark, Spain and New Zealand (GBIF 2021), all of these records likely represent different species, or introduced populations.
Population in western North America is known from two sites in California, fifteen sites scattered through the Siskiyou and Cascade Range in Oregon, and the Rocky Mountains. No decline has been noted, but limited data is available to assess trends.
Hypogeous to erupting from duff. Ectomycorrhizal, reportedly associated with Pinaceae (Abies, Tsuga, Picea, and Pinus spp.). Most western North American collections come from high elevation, relative dry forest. Fruiting in summer and fall. This species is dependent on mycophagy (primarily eaten by small mammals) for spore dispersal. Many Rhizopogon species have spores which stay viable in soil for many years; waiting for conditions to be optimal before growing. It is unknown if Rhizopogon abietis is one of the ‘sporebank’ species.
Prolonged droughts and decades of fire suppression have drastically altered western montane forests, leading to thicker, denser, Abies dominated forests. As a result, hotter, stand replacing fires (rather than patchwork and understory burns) are commonplace, altering appropriate habitat drastically, and making it ill-suited for this species.
This species is included on the United States Forest Service Northwest Forest Plan Survey and Manage list of rare/old growth forests dependent fungi (Castellano et al. 2003).
Modern taxonomic work on this group of Rhizopogon; comparing western North American and eastern North American collections.
Castellano, M., Cázares, E., Fondrick, B. and Dreisbach, T. 2003. Handbook to Additional Fungal Species of Special Concern in the Northwest Forest Plan. General Technical Report PNW-GTR-572. United States Department of Agriculture.
GBIF. 2021. Global Biodiversity Information Facility. https://www.gbif.org/
MyCoPortal. Mycology Collections Portal. Available at: http://mycoportal.org
Siegel, N., Vellinga, E.C., Schwarz, C., Castellano, M.A. and Ikeda, D. 2019. A Field Guide to the Rare Fungi of California’s National Forests. Bookmobile: Minneapolis, MN. 313 p.
Smith, A.H. and Zeller, S.M. 1966. A preliminary account of the North American species of Rhizopogon. Memoirs of the New York Botanical Garden. 14: 1–178