Rhizopogon alexsmithii

(Trappe) Vizzini & Zotti

a fungus

G2Imperiled Found in 4 roadless areas NatureServe Explorer →
G2ImperiledGlobal Rank
EndangeredIUCN
UnknownThreat Impact
Identity
Unique IDELEMENT_GLOBAL.57.9775
Element CodeNFNHP00006
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryFungus
IUCNEndangered
Endemicoccurs (regularly, as a native taxon) in multiple nations
KingdomFungi
PhylumBasidiomycota
ClassBasidiomycetes
OrderBoletales
FamilyRhizopogonaceae
GenusRhizopogon
Synonyms
Alpova alexsmithiiTrappe
Concept Reference
Trappe, J.M. 1975. A revision of the genus Alpova with notes on Rhizopogon and the Melanogastraceae. Nova Hedwigia Beih. 51:279-309
Taxonomic Comments
Species Fungorum (2018) transfers Alpova alexsmithii to Rhizopogon alexsmithii.
Conservation Status
Rank MethodLegacy Rank calculation - Biotics v1
Review Date2019-03-25
Change Date2004-05-14
Edition Date2019-03-29
Edition AuthorsFrancisco J. Camacho (2002), rev. C. Lawrence and M. Trappe (2017), rev. Treher (2019)
Threat ImpactUnknown
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences6 - 20
Rank Reasons
Rhizopogon alexsmithii occurs from mid to high elevation old growth Tsuga forests in the Cascade Mountains of Oregon, Washington, and British Columbia. Sites from Washington and British Columbia are historic but the species is extant, based on recent collections, in Oregon. The species is threatened, with its host species, by fire, logging, road maintenance, and recreation. The species is suffering from habitat declines, which is likely exasperated by limited dispersal capabilities.
Range Extent Comments
Rhizopogon alexsmithii occurs along the upper Cascades from Lane County, Oregon and Washington and in Vancouver, British Columbia, Canada (N. Siegel, pers. comm., )
Occurrences Comments
The only recent collections for this species are from Oregon (Mt. Hood National Forest). There are historic additional historic occurrences from Oregon, Washington (1), and British Columbia (1).
Threat Impact Comments
This species occurs in old growth forest that has and continues to decline due to logging and stand replacing fires. Recreation related development, including roads for recreational activities and campgrounds, is a threat. Foot traffic, primarily around campgrounds, is a threat, as it compacts the soil.
Ecology & Habitat

Habitat

Rhizopogon alexsmithii is a "hypogeous, mycorrhizal sequestrate species forming mycorrhiza with the roots of mature to old-growth Abies procera, A. lasiocarpa, Tsuga mertensiana or Tsuga heterophylla (Castellano and Bérubé 2015)."

Reproduction

The fungi is dispersed by small mammals that ingest the fruiting mushrooms.Their home range is less than 2 ha (Castellano and Bérubé 2015).
Terrestrial Habitats
Forest/WoodlandForest - Conifer
Other Nations (2)
United StatesN2
ProvinceRankNative
OregonS2Yes
CanadaN2
ProvinceRankNative
British ColumbiaS2Yes
Threat Assessments
ThreatScopeSeverityTiming
5 - Biological resource useUnknownUnknownHigh (continuing)
5.3 - Logging & wood harvestingUnknownUnknownHigh (continuing)
6 - Human intrusions & disturbanceRestricted - smallUnknownHigh (continuing)
6.1 - Recreational activitiesRestricted - smallUnknownHigh (continuing)
7 - Natural system modificationsPervasive (71-100%)UnknownHigh (continuing)
7.1 - Fire & fire suppressionPervasive (71-100%)UnknownHigh (continuing)
7.1.1 - Increase in fire frequency/intensityPervasive (71-100%)UnknownHigh (continuing)

Plant Characteristics
DurationEPHEMERAL FRUITING BODY
Economic Value (Genus)No
Roadless Areas (4)
Oregon (4)
AreaForestAcres
Maiden PeakDeschutes National Forest26,432
Maiden PeakWillamette National Forest9,627
Waldo - FujiWillamette National Forest15,273
Waldo - Salmon CreekWillamette National Forest3,195
References (7)
  1. Castellano, M. A., J. E. Smith, T. O'Dell, E. Cazares and S. Nugent. 1999. Handbook to strategy 1 fungal species in the Northwest Forest Plan. USDA Forest Service General Technical Report PNW-GTR-476. Northwest Research Station, Portland, OR. 195 pp. Online. Available: https://www.fs.usda.gov/pnw/pubs/pnw_gtr476.pdf
  2. Castellano, M. &amp; Bérubé, J. 2015. <i>Rhizopogon alexsmithii</i>. <i>The IUCN Red List of Threatened Species</i> 2015: e.T75121617A75121859. <a href="http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T75121617A75121859.en">http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T75121617A75121859.en</a>. Downloaded on 25 March 2019.
  3. Dahlberg, A., and Mueller, G.M. 2011. Applying IUCN red-listing criteria for assessing and reporting on the conservation status of fungal species. Fungal Ecology 4(2):147-162.
  4. Index Fungorum and Species Fungorum. 2018. <i>In</i> Index Fungorum-Species Fungorum (<a href="https://indexfungorum.org" target="_blank">https://indexfungorum.org</a> and <a href="https://speciesfungorum.org" target="_blank">https://speciesfungorum.org</a>) database export on 16 June 2018. Royal Botanic Gardens, Kew.
  5. Index Fungorum and Species Fungorum. 2025. <i>In</i> Index Fungorum-Species Fungorum (<a href="https://indexfungorum.org" target="_blank">https://indexfungorum.org</a> and <a href="https://speciesfungorum.org" target="_blank">https://speciesfungorum.org</a>) database export on 29 September 2025. Royal Botanic Gardens, Kew.
  6. MycoBank. 2025. MycoBank database download, export date January 2025. International Mycological Association. [http://www.mycobank.org]
  7. Trappe, J.M. 1975. A revision of the genus <i>Alpova </i>with notes on <i>Rhizopogon </i>and the Melanogastraceae. Nova Hedwigia Beih. 51:279-309