A small to medium-sized mushroom with an orange-brown to reddish-orange cap, bright to deep red gills, and rusty orange spores. It has bee reported with Lodgepole Pine (Pinus contorta ssp. murrayana) in the Sierra Nevada mountains, often near lakes, streams or other water sources. Infestation by bark beetles and changes in fire frequency and intensity are threatening its habitat leading to a inferred population decline. 
Because of its bright reddish brown to orange brown colors, this is an easily seen species, thus the few number of reports suggests that this may be a very rare species. Additionally, this is a target species of the Fungal Diversity Survey West Coast Rare Fungus Challenge that is engaging citizen scientists to search for rarely recorded fungi in the region. This focused effort has only recovered two records (inaturalist.org). Thus, taking a precautionary approach it is estimated that that its population size is less than 1000 - 1,500 occurring in small scattered subpopulations).  It is assessed and Endangered. 

First described as Dermocybe sierraensis (Ammirati, 1989), it was later transferred to the gunus Cortinarius (Niskanen et al. 2013).

A small to medium-sized mushroom with an orange-brown to reddish-orange cap, bright to deep red gills, and rusty orange spores. It grows with Lodgepole Pine (Pinus contorta ssp. murrayana) in summer and fall.

Rare; only known from four locations in higher elevation Lodgepole Pine forests in the Sierra Nevada mountains, often near lakes, streams or other water sources.

Known from five sites in the southern, central, and northern Sierra Nevada in California, USA (mycoportal.org, inaturalist.org, December 2024).

Currently this species is known from five collections / observations, two of which are historic. Subpopulations are from high elevation Lodgepole Pine (Pinus contorta) forests near water sources. Until 2023 it was only known from southern and central Sierra Nevada Mountains. An observation in 2023 from Lassen Volcanic National Park extended its known distribution in the northern part of the mountain range. Because of its bright reddish brown to orange brown colours, this is an easily seen species, thus the limited number of reports supports that it is a very rare species. Additionally, this is a target species of the Fungal Diversity Survey West Coast Rare Fungus Challenge that is engaging citizen scientists to search for rarely recorded fungi in the region. This focused effort has only recovered two records (inaturalist.org). Thus, taking a precautionary approach it is estimated that that its population size is approximately 1,000-1,500 mature individuals. This is based on; five known functional individuals multiplied by an estimated factor of 200-300 to take into account the conversion to mature individuals, per Dahlberg and Mueller (2011) and additional potential sites based on potential habitat, that have not been recorded so far. It is thought to occurs in small scattered subpopulations, consisting of fewer than 250 mature individuals.

Ectomycorrhizal. Fruitbodies scattered, growing from duff and soil under Lodgepole Pine (Pinus contorta ssp. murrayana). Only known from a few locations in higher elevation Lodgepole Pine forests in the Sierra Nevada mountains, often near lakes, streams or other water sources. Fruiting in summer and early fall.

Mountain pine beetle outbreaks, leading to large scale dieback in Lodgepole Pine forest and an increase in fire frequency and intensity are likely detrimental to this species. Cortinarius sierraensis may also be indiscriminately collected if found by dyers. Based on the limited information on the species’ distribution and details of its habitat preference additional threats may be important.

Protect known populations from logging, development and other disturbance.

Targeted surveys of suitable habitat to assess presences or absents of this species.

Closely related species of Cortinarius are highly prized dye fungi. Cortinarius sierraensis would likely be collected if found by dyers.

Ammirati, J.F. 1989. Dermocybe, subgenus Dermocybe, section Sanguineae in Northern California. Mycotaxon 34: 21–36.

inaturalist.org (December 2024).

Niskanen, T., K. Liimatainen, J.F. Ammirati & K. Hughes. 2013. Cortinarius section Sanguinei in North America. Mycologia 105: 344–356.

Wood, M. & F. Stevens. 2017. Mykoweb, Fungi of California.  http://mykoweb.com/CAF/species/Cortinarius_sierraensis.html