Notes on HYDNELLUM in the Pacific Northwest

Prepared for the Pacific Northwest Key Council

By Ian Gibson, South Vancouver Island Mycological Society

Copyright ã 2019 Pacific Northwest Key Council

Concepts are not yet clear enough to provide a trial Key to Hydnellum Species in the Pacific Northwest. Most amateur mycologists in the Pacific Northwest will recognize what have been referred to as Hydnellum aurantiacum, Hydnellum caeruleum, Hydnellum peckii and Hydnellum suaveolens. Those who are particularly interested would probably also recognize Hydnellum regium and would be able to track down an identification for Hydnellum geogenium and Hydnellum cyanopodium if they were lucky enough to find them. But a key is not needed.

Most amateurs would also recognize a form of toothed mushroom that has been called Hydnellum. The fruitbody is tough, fibrous to spongy, and grows on the ground under conifers, often engulfing twigs as it grows, and sometimes fusing with other fruitbodies. The cap surface is often zonate, depressed, bumpy or ridged, and its outline is rarely completely circular. Cutting it in half often reveals different color areas in the cap and stem flesh. Spore deposits are brown. Sarcodon species in contrast are firm and fleshy but not tough, flesh is less likely to have color zones, and the caps are closer to circular in outline. Some Sarcodon species are easy to recognize (Sarcodon imbricatus, Sarcodon squamosus, Sarcodon fuscoindicus, and Sarcodon scabrosus).


1.      There are many other described Hydnellum and Sarcodon species that may or may not occur in the Pacific Northwest, and undescribed species probably occur here. Sometimes the other described species have vague or controversial concepts which vary among authors. What we find often does not correspond easily to available descriptions.

2.      Hydnellum aurantiacum is not a single species but a group of species and should be identified only to group.

3.      Hydnellum diabolum may or may not be a separate species from Hydnellum peckii.

4.      The borderline between Sarcodon and Hydnellum has never been clearly defined. Larsson et al.(2019) show that Sarcodon and Hydnellum are closely interrelated, and to be consistent, most of our “Sarcodon” species need to be renamed as Hydnellum species. If we follow the changes that the study makes, S. fuscoindicus is Hydnellum fuscoindicum, Sarcodon scabrosus is Hydnellum scabrosum, S. imbricatus and S. squamosus remain in Sarcodon, S. atroviridis may have a different status, and both S. stereosarcinon and S. calvatus are undetermined [but on spore size criteria are more likely to be in Hydnellum]. The morphological concepts of the two genera need to be rewritten, and it is not yet clear how to do this.


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Baird, Richard E.  1986a.  “Type studies of North American and other related taxa of stipitate hydnums: Genera Bankera, Hydnellum, Phellodon, Sarcodon.”  Bibliotheca Mycologica Band 103: 1-89. 

Baird, Richard E.  1986b.  “Study of the stipitate hydnums from the Southern Appalachian Mountains – Genera: Bankera, Hydnellum, Phellodon, Sarcodon.” Bibliotheca Mycologica Band 104: 1-156.

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Harrison, K.A.  1961. The Stipitate Hydnums of Nova Scotia. Can. Dep. Agric. Publ. 1099. Ottawa. 60 pp.

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Larsson, Karl-Henrik, Sten Svantesson, Diana Miscevic, Urmas Kõljalg, Ellen Larsson. 2019. “Reassessment of the generic limits for Hydnellum and Sarcodon (Thelephorales, Basidiomycota)”. MycoKeys 54: 31-47.