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Summary: Ganoderma oregonense forms large yellow-brown to red-brown semicircular or fan-shaped brackets with a lacquer-like surface, growing on conifers. Many consider this a synonym of Ganoderma tsugae Murrill, Bull. Torrey bot. Club 29: 601. 1902. Gilbertson(1) distinguish them on the following features [while saying they are doubtfully distinct]: Ganoderma oregonense has a cap up to 100cm x 40cm x 20cm, 2-3 pores / millimeter, and spores 13-17 x 8-10 microns, whereas Ganoderma tsugae has cap up to 20cm x 30cm x 7cm, 5-6 pores per millimeter, and spores 13-15 x 7.5-8.5 microns, (Ginns(25)). Ganoderma oregonense is found in BC, WA, OR, ID, and also CA, MT, and NV.
Cap: up to 100cm across, 40cm wide, 20cm thick, semicircular or fan-shaped; "yellowy brown to dark reddish brown or mahogany, with concentric bands of color; quickly develops a shiny, waxy crust that cracks extensively in older specimens", (Phillips), up to 100cm wide, 40cm deep, and 20cm thick, without a stem or with a rudimentary lateral stem, single or occasionally imbricate [shingled], annual; upper surface ochraceous to dark reddish brown or mahogany, often distinctly concentrically zoned; quickly developing shiny lacquered crust, crust cracking extensively on older specimens, (Gilbertson)
Flesh: up to 15cm thick, "soft-fibrous; cream-colored to pale buff", (Phillips), up to 15cm thick, "soft-fibrous, homogeneous and azonate or with a thin firmer layer with thin darker lines directly under the surface crust", cream-colored to pale buff, (Gilbertson)
Pores: 2-3 per mm, circular to angular; cream colored bruising brown or purplish brown; tube layer up to 3cm thick, pale purplish brown, (Phillips), 2-3 per mm, circular to angular, with thin entire walls; "cream colored at first, bruising or drying wood brown to pale purplish brown"; tube layer up to 3cm thick, distinct from flesh, pale purplish brown, (Gilbertson)
Stem: with no stem or small lateral stem-like attachment (Phillips)
Odor: none (Miller)
Taste: unknown (Miller)
Microscopic: spores 13-17 x 8-10 microns, elliptic, with truncate apex, inamyloid, pale brown in KOH, "wall with two layers separated by interwall pillars, outer wall with pronounced depressions and appearing rough"; cystidia absent; hyphal system trimitic: context generative hyphae 2.5-5 microns wide, "thin-walled, with clamps, rarely branched"; context skeletal hyphae 3-5 microns wide, colorless, thick-walled, non-septate, with occasional branching, context binding hyphae 2-4.5 microns wide, colorless, thick-walled, non-septate, with frequent branching, trama hyphae similar; cap surface with dense palisade of clavate, thick-walled strongly amyloid end cells, up to 70 microns long and 8.5-11 microns wide at widest point, (Gilbertson)
Spore Deposit: rusty brown (Phillips, Gilbertson)
Habitat / Range
annual, commonly on dead standing conifers and on conifer stumps, main substrates are Abies (fir) and Tsuga (hemlock), causes white butt and root rot of living and dead conifers, (Gilbertson), fruiting in spring, summer, and fall, (Miller)
Ganoderma tsugae of eastern North America, California and Arizona is similar but "Ganoderma oregonense is doubtfully distinct from G. tsugae, differing mainly in the large size of the basidiocarps, larger pores, and slightly larger spores", (Gilbertson(1) who note also for G. tsugae that the stem is often vertical and well-developed). "Ganoderma oregonense and G. tsugae may be names for the same fungus (Gilbertson and Ryvarden 1986, Moncalvo et al. 1995)", but Gilbertson and Ryvarden distinguished them on the following features: basidiocarps up to 100cm x 40cm x 20cm for G. oregonense, 20cm x 30cm x 7cm for G. tsugae, pores 2-3 per millimeter for G. oregonense, 5-6 per millimeter for G. tsugae, and spores 13-17 x 8-10 microns for G. oregonense, 13-15 x 7.5-8.5 microns for G. tsugae, (Ginns(25), the quotation having Latin names in italics). 'Very young specimens of Fomitopsis pinicola may be more or less completely "varnished" but the varnish disappears as the basidiocarp ages. The very dense, hard context of F. pinicola is very different from the light, soft-punky context of G. oregonense.', (Ginns(25), with Latin names italicized). Ganoderma lucidum is rare in the Pacific Northwest and grows on hardwoods. Ganoderma applanatum and Ganoderma brownii do not have a varnished appearance.
Recommended citation: Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2019. E-Flora BC:
Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for
Advanced Spatial Analysis, Department of Geography, University of British
Columbia, Vancouver. [Accessed:
18/11/2019 6:17:06 AM
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