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

Summary:
Meripilus sumstinei forms large multicapped fruitbody with ochraceous to brown, fan-shaped to spatula-shaped caps arising from a common base. The pore layer bruises blackish. It is rare in the Pacific Northwest. This fungus has been referred to in North America as Meripilus giganteus (Fr.) P. Karst. which is a European species.

Meripilus sumstinei was found in Victoria BC in 2016 (according to Adolf and Oluna Ceska, pers. comm.). Ginns(28) says that the only report of Meripilus sumstinei from west of the Mississippi is from ID (according to 1914 report by Weir in Phytopathology 4: 271-276 referred to in Gilbertson(1) (as M. giganteus)), but this was written prior to the 2016 Ceska report. It has also been found in AL, IA, IL, IN, LA, MA, MD, MO, NC, NJ, NY, OH, PA, TN, VA, WI, and WV, (Gilbertson as M. giganteus).

Cap:
numerous 5-20cm caps arising from common base or stem, the fruitbody as a whole up to 30cm wide, caps fan-shaped to spathulate, narrowing downward, fleshy when fresh, hard and brittle when dry; "ochraceous to brown when old, often somewhat concentrically zonate"; bald, smooth, when dry the thinner parts often radially wrinkled; margin thin, entire to lobed and wavy, often deflexed [downcurved] when dry, (Gilbertson), " 50-80cm across, rosettelike, consisting of numerous flattened fanshaped caps around common base", caps 5-25cm, 1-2cm thick, spoon-shaped with thin sharp margin; "grayish to dull yellow, becoming smoky and dark with concentric zones of lighter and darker brown; radially grooved and covered in very fine brown scales", (Phillips), 5-20cm, semicircular to fan-shaped or spoon-shaped with thin sharp margin; grayish to yellowish drab, becoming smoky and dark, blackening along the margin; finely hairy or fibrous, radially wrinkled, caps forming clusters typically weighing 3 to 10 pounds, (Lincoff)

Flesh:
up to 1.5cm thick near bases of individual caps; whitish to cork-colored, lighter in color than tubes, (Gilbertson), soft, fibrous; white, (Phillips), 0.1-1cm thick; white, (Lincoff)

Pores:
3-5 per mm, "white to wood-colored, darkening when touched in fresh condition"; tube layer up to 0.8cm thick, colored as pore surface, (Gilbertson), "pores small, often late in forming; cream", tube layer 0.1-0.5cm thick, whitish bruising blackish, (Phillips), 4-7 per mm, angular, becoming torn; white, bruising blackish; tube layer 0.1-0.3cm thick, (Lincoff)

Stem:
numerous imbricate [shingled] caps with tapering base arising from common base or stem which is fibrous, short and stout or almost absent, ochraceous, and smooth, (Gilbertson), very short and thick; ocher; smooth or fibrous, (Phillips)

Odor:
pleasant (Phillips), unpleasant but not distinctive (Miller)

Taste:
slightly sour (Phillips), mild but somewhat acrid [peppery] (Miller)

Microscopic:
spores 6-7 x 4.5-6 microns, broadly elliptic to nearly round, smooth, inamyloid, colorless, thin-walled; basidia 4-spored, 22-40 x 7-8 microns, clavate; cystidia absent, "fusoid cystidioles present, 18-40 x 5-8 microns, simple septate at base"; hyphae monomitic, generative hyphae 3-5 microns wide, with simple septa, in the trama more or less parallel, thin-walled and with numerous septa, in context and stem generative hyphae 6-14 microns wide, unbranched or sparingly branched, strongly thick-walled to almost solid, with scattered to almost no septa, mixed with more twisted and branched hyphae, some very thick-walled and swollen, others more thin-walled and of more even width, transitions occurring among all these types of hyphae, width variable from 3-10 microns, in swollen parts and around points of branching up to 15 microns wide, (Gilbertson)

Spore Deposit:
white (Lincoff)