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Hydnellum cyanopodium K.A. Harrison

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Scientific name
Hydnellum cyanopodium
K.A. Harrison
Common names
IUCN Specialist Group
Mushroom, Bracket and Puffball
Assessment status
Assessment date
IUCN Red List Category
Siegel, N.
Dahlberg, A.

Assessment Notes

The content on this page is fetched from The IUCN Red List of Threatened Species: https://www.iucnredlist.org/species/95384499/95385474


The hydnoid fungus Hydnellum cyanopodium is a conspicuous and rare fungus forming ectomycorrhiza with Sitka Spruce (Picea sitchensis). It is seemingly restricted to mature and old growth forests of the southern portion of the Sitka Spruce range on the coast of Western USA. Easily recognized by its bluish to bluish purple color of the sporocarps, bluish interior flesh,  droplets on the margin when young, and mycorrhizal association with Sitka Spruce. The long lasting, and distinctive sporocarps along with the bluish color leads us to think that the species would get noticed if it was more common. However, despite having near-continuous annual fruitings, long lasting sporocarps, and considerable mycological activities during the last decades, it is currently (2017) only known from seven locations on the coast of California and Oregon. It is common in two small spruce groves in California, but elsewhere rare. 

The known number of sites of this striking and much looked after fungus is seven and the estimated total number of localities is estimated to be less than 70; with small populations of 1-10 genetically unique mycelial individuals each. Hence the total number of mature individuals is estimated to be less 6,000. The species is assessed as Least Concern.

Coastal forests have been extensively logged for timber during the last century and logging is ongoing, resulting in decline and fragmentation of available habitat. The projected habitat decline is an estimated 20-25% over the southern half of its range over the next 50 years, due to the loss of habitat to logging and urban development, and the stress and loss of Sitka Spruce due to reduced moisture from fog and via climate change. The species needs to be monitored as listing under a more threatened Red List Category may be warranted.

Taxonomic notes

Harrison (1964) described Hydnellum cyanopodium from a A.H. Smith collection made in 1937 from Crescent City, California. All suitable habitat from this area has been since lost; due to logging, farmland development and urban sprawl.

Hydnellum cyanopodium is easily recognized by it’s bluish to bluish purple color of the sporocarps, bluish interior flesh, reddish droplets on the margin when young, and presumed mycorrhizal association Sitka Spruce (Picea sitchensis).

Hydnellum cyanopodium could be mistaken for Hydnellum caeruleum, H, regium, or H. peckii. Hydnellum caeruleum differs by having sky blue to brown velvety cap, whitish, blue to brown spines, and most distinctly by the orange flesh in the stem and zoned, bluish and orange flesh in the cap. Hydnellum regium has a darker, bluish black to black cap, darker spines, more fleshy texture to the sporocarp, and has pale to orangish flesh in the stem, transitioning to gray or black cap flesh. It is more common in more northern portions of the Sitka Spruce range, and with Engelmann Spruce (Picea engelmannii) in the Cascade and Rocky Mountain ranges. Hydnellum cyanopodium superficially resembles Hydnellum peckii when young, and covered with red droplets; the brown colors and strongly acrid taste easily distinguishes H. peckii.

Geographic range

Hydnellum cyanopodium is known from the central Humboldt County coast in California to Clatsop County on the northern Oregon coast in the US; a stretch of 650 km. All known sites in the southern half of the range are within 1 km of the coast, a couple of the northern sites are slightly more inland (following the distribution of Sitka Spruce), but are still within 3 km of the coast. There are two unconfirmed sightings (bad photos posted on social media) from Haines, Alaska that may represent this species; however, despite a number of surveys in coastal British Columbia, Canada and southeast Alaska, no records exist from these efforts.

Population and Trends

Hydnellum cyanopodium is only known from seven sites on the Oregon and Californian coast, (plus two unconfirmed sightings in Haines, Alaska). It is locally common in two small spruce groves on the Humboldt County, California coast (most of the Mushroom Observer observations come from these sites). These sites suffered from the drought of 2013-2015, and abnormally warmer temperatures and significantly less fog (Johnstone and Dawson 2010).

The estimated total number of localities (including undiscovered ones) is less than 70, usually with small populations of 1-10 gentically unique individuals each, giving corresponding to less than 3,000 to 6,000 mature individuals in total (cf. Dahlberg and Mueller 20111).

Because of the limited reports, and understanding of this species, it’s tough to assess the trend. The greater part of suitable habitat within its distribution in California and Oregon has been lost during the last 100 years; due to logging, farmland development and urban sprawl. The continued decline of suitable habitat suggest that this species is deteriorating.

Population Trend: decreasing

Habitat and Ecology

Hydnellum cyanopodim forms ectomycorrhizae with Sitka Spruce (Picea sitchensis) and grows in open understory of mature to old growth, mossy forests on the immediate coast. As for most ectomycorrhizal fungi, the individual mycelia, the unique genotype, is long-lived, may persist many decades or more and can potentially live as long as the there is a continuous local presence of its host trees.


Coastal forests have been extensively logged for timber during the last century and logging is ongoing, resulting in decline and fragmentation of available habitat. Forest understory vegetation has changed during the last 30 years, with an increase of Polystichum, Gaultheria shallon and Vaccinium ovatum, resulting in a decrease of open forest with a mossy substrate.

Global climate change is potentially devastating to coastal Sitka Spruce forest; especially in the southern part of the range, where this fungus is most prevalent. These trees depend on summer fog and winter rains. Due to climate change, the fog patterns have changed considerably during the last 100 years with a significant decrease of extent of fog in summer (Johnstone and Dawson 2010), and winter rains are inconsistent during the last 10 years. Dryer, hotter summers and loss of fog is stressing southern populations of Sitka Spruce.

Continued coastal urban development, especially in Oregon will fragment habitat and contribute to habitat loss.

Conservation Actions

Most known locations for Hydnellum cyanopodium are on protected federal and state park lands, but park managers should be made aware of this species.

Confirmation that it occurs in Alaska is critical to establish if the unsubstantiated records are this species, or if it is restricted to northern California and Oregon. Because of the distinctive and showy color and long lasting sporocarps, this would be a good species for citizen scientists to search for additional locations in California and Oregon, and attempt to locate populations in Washington and British Columbia.

Source and Citation

Siegel, N. 2017. Hydnellum cyanopodium. The IUCN Red List of Threatened Species 2017: e.T95384499A95385474. https://dx.doi.org/10.2305/IUCN.UK.2017-3.RLTS.T95384499A95385474.en .Accessed on 1 February 2024

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