Ganoderma oregonense

The western varnish shelf, Ganoderma oregonense Murrill, collected at Salt Point State Park, Sonoma Co., California, USA.


Ganoderma nevadense Murrill
N. Amer. Fl. (New York) 9(2): 119 (1908)
Ganoderma sequoiae Murrill
N. Amer. Fl. (New York) 9(2): 119 (1908)

Common name

Western varnish shelf
Oregon polypore
Lacquer fungus


Fruiting bodies are large (typically up to 20 cm in diameter and 5 cm thick, although they may grow to be much larger) semicircular or fan-shaped, and usually sessile, although some specimens may have a small lateral stem-like attachment to its host tree. The cap surface is smooth, with a thin and brittle crust, and shines as if varnished (laccate), dark reddish brown in color, sulcate, zonate with rings distant on the surface and crowded at the margin, more or less rugose. The context is white to cream-colored, cinnamon-colored next to the pore surface, and soft.

Originally described by Murrill (1908), the distribution of this species is limited to the Pacific west and northern California, growing on conifers other than species of Pinus (Overholts, 1953). It causes a white spongy rot (Englerth, 1942), and has been shown to cause extensive delignification (Adaskaveg et al., 1990). Basidiospores are ovate in shape, with a tapering apex and slightly roughened walls, with a mean length of 13-15.5 x 7.5-9.0 µm. Pilocystidia are strongly amyloid, thick-walled long-shafted and clavate in shape, 7-12 um in diameter and with no apical projections (Adaskaveg and Gilbertson, 1988). G. oregonense has been shown be be closely related to G. tsugae and G. valesiacum by phylogenetic analysis of small-subunit rDNA sequences (Hong and Jung, 2004).

Ganoderma oregonense from Corvallis, Orgeon
A cross-section of the Oregon polypore (from Atkinson, 1908).

Medicinal properties

Antibacterial effects

An antibiotic highly active against Gram+ and acid-fast bacteria has been isolated from G. oregonense and named “oregonensin” (Florey, 1949). Oregonensin (C20H32O8) inhibits Staphylococcus aureus growth in broth at 1.25 µg/mL, and Mycobacterium phlei at 5 µg/mL.

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Adaskaveg JE, Gilbertson RL. (1988).
Basidiospores, pilocystidia, and other basidiocarp characters in several species of the Ganoderma lucidum complex.
Mycologia 80(4):493-507.

Adaskaveg JE, Gilbertson RL, Blanchette RA. (1990)
Comparative studies of delignification caused by Ganoderma species.
Appl Environ Microbiol. 56(6):1932-1943.

Atkinson GF. (1908).
Observations on Polyporus lucidus Leys and some of its allies from Europe and North America.
Botanical Gazette 46(5):321-338.

Brian PR.
Antibiotics produced by fungi. (1951).
The Botanical Review 17(6):357-430.

Englerth GH. (1942).
Decay of western hemlock in western Oregon and Washington.
Yale Univ Sch Forest Bull 50:1-53.

Florey HW, Chain E, Heatley NG, Jennings MA, Sanders AG, Abraham EP, Florey ME. (1949).
Antibiotics: A survey of penicillin, streptomycin, and other antimicrobial substances from fungi, actinomycetes, bacteria and plants.
Oxford University Press/Oxford Medical Publications, London. p. 362.

Hong SG, Jung HS. (2004).
Phylogenetic analysis of Ganoderma based on nearly complete mitochondrial small-subunit ribosomal DNA sequences.
Mycologia 96(4): 742-755.

Overholts LO. (1953).
Polyporaceae of the United States, Alaska, and Canada.
University of Michigan Press, Ann Arbor. 466 pp.

Steyaert RL. (1980).
Study of some Ganoderma species.
Bull Jard Bot Nat Belg. 50:135-186.

3 thoughts on “Ganoderma oregonense”

  1. Hi. What is the difference between ganoderma lucidum and oregonese, besides that one grows from the root and the other from the stam. I often find both in Croatia/ Eastern Europe and am interested if they are the same or maybe just a bit different.
    Best, Erni

    • Hi Erni,

      There really isn’t too much of a difference between Ganoderma Lucium and Ganoderma Oregonense. Oregonense has larger spores. There is a compelling argument that Ganoderma Lucium, Oregonense, Tsugae, and Curtisii should be considered one species. The reason they are different species is because their hosts are different.


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