E-Flora BC: Electronic Atlas of the Flora of British Columbia

Summary:
Features include 1) an annual brown pore surface growing flat and firmly attached on conifer wood especially Douglas-fir, 2) when fresh with a narrow white, fringed margin, 3) soft flesh that is light in weight, and 4) microscopic characters including colorless oval spores, and conspicuous setal hyphae that project into the tubes. |What was thought to be a variation of Phellinidium weirii that affects Douglas-fir, true firs, and hemlock (as opposed to the one that affects Western Red-cedar and Alaskan Yellow-cedar) is now regarded as Phellinidium sulphurascens Pilat. Larsen et al. (1994) summarize the criteria for separating P. sulphurascens and P. weirii: 1) P. weirii usually occurs on Western Red-Cedar, whereas P. sulphurascens usually occurs on conifers other than Western Red-Cedar [such as Douglas-fir], 2) fruitbodies are usually perennial in P. weirii and usually annual in P. sulphurascens, 3) sporulation occurs in spring / mid-summer in P. weirii and in late summer / fall in P. sulphurascens, 4) in North America, pathogenesis by P. weirii does not result in death of the host - stem breakage is caused by butt-rot, but with P. sulphurascens in North America pathogenesis involved with root-rot results in death of the host and windthrow associated with "root-ball", 5) spores eventually have 2 germ tubes and germ tubes and juvenile mycelia are 2-3.5 microns wide in P. weirii, whereas spores have one germ tube and germ tubes and juvenile mycelia are 4.5-6 microns wide in P. sulphurascens, 6) dimensions of setal hyphae in wood and test tube culture are greater in P. sulphurascens, 7) columnar tufts of hyphae are present in test tube cultures at 6 weeks in P. weirii but not in at 6 weeks in P. sulphurascens, (Larsen, M.J.(11)). |The online Species Fungorum, accessed May 29, 2020, listed the current name as Coniferiporia sulphurascens, but MycoBank, accessed the same day, listed the current name as Phellinidium sulphurascens with Coniferiporia as an obligate or homotypic synonym.

Larsen, M.J.(11) used collections of P. sulphurascens from BC, WA, OR, ID, CO, and Russia and collections of P. weirii from British Columbia, Washington, Oregon, Idaho, and Alaska. P. sulphurascens occurs in southern BC, WA, OR, northern CA, western MT, northern ID, Russia, China, and Japan. P. weirii occurs in Washington, Oregon, Idaho, and Montana, (Gilbertson, including any P. sulphurascens collections).

Cap:
growing flat on wood with pore surface exposed, spreading out extensively, light in weight, not readily separable; margin up to 2cm wide, soft, fimbriate [fringed], pale brown, (Gilbertson description of P. weirii sensu lato that includes this species), fruitbodies of Douglas-fir form [P. sulphurascens] light buff with narrow white margin when fresh, becoming a uniform dark color when old, (fruitbodies of P. weirii perennial and typically darker in color); "White to tawny to mauve mycelium (ectotrophic mycelium) can usually be found on or in bark at the root collar and on the roots, particularly in mineral soil. A brown, crust-like mycelial growth often occurs growing over the ectotrophic mycelium on or near the root collar, on infected roots, and on exposed advanced decay.", the crust-like mycelium has the appearance of blistering paint, diseased trees with advanced root decay are frequently windthrown, producing typical root balls, (Allen)

Flesh:
up to 1cm thick, soft, fibrous, spongy; not zoned, yellowish brown, (Gilbertson for P. weirii sensu lato)

Pores:
pores small and somewhat irregular in Douglas-fir form, [P. sulphurascens], (pore surface smoother and pores more regular in on Western Red-cedar form [P. weirii sensu stricto]), (Allen)

Microscopic:
spores 4.5-6 x 3.5-4.5 microns, oval, smooth, inamyloid, colorless; basidia 4-spored, 10-11 x 5-5.5 microns, clavate, simple-septate at base; hymenial setae absent but projecting setal hyphae abundant, projecting up to 70 microns, 6-10 microns thick, straight, pointing toward the tube opening; hyphae of context of 2 other types: 1) 2.5-5.5 microns thick, "pale yellowish brown in KOH, thin-walled, with frequent branching, simple-septate", 2) 3-5.5 microns wide, "darker brown in KOH, thick-walled, with rare branching", (Gilbertson for P. weirii sensu lato), setal hyphae averaging 507.2 microns (with standard deviation 119 microns) x 6.2 microns (with standard deviation 1.3 microns), (Larsen, M.J.)