Pseudomerulius aureus (Fr.) Julich
no common name
Tapinellaceae

Species account author: Ian Gibson.
Extracted from Matchmaker: Mushrooms of the Pacific Northwest.

Introduction to the Macrofungi

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Map

E-Flora BC Static Map

Distribution of Pseudomerulius aureus
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Species Information

Summary:
Features include 1) resupinate growth on decayed, barkless, confer wood, especially pine, 2) a radial or net-like spore-bearing surface (folded-wrinkled, often raduloid), soft, wax-like, yellow or almost orange, then yellow-brown, darkening when touched, 3) a margin that is narrow, and bright yellow to whitish, 4) a cap when present that is pallid or yellowish, tomentose, not zoned, 5) spores that are cylindric to suballantoid, smooth, yellow, in Melzer''s reagent with slight reddish brown tint, and cyanophilic, with walls slightly thickened, 6) basidia formed from the area opposite to a basal clamp connection, and 7) a monomitic hyphal system, the clamp connections often large or handle-like, some hyphae with conidia-like outgrowths, some hyphae with bands at intervals, the subicular hyphae with grainy encrustation.
Microscopic:
SPORES 4-4.5(5) x 1.3-1.8 microns, cylindric, "straight or with slightly concave adaxial side, or suballantoid", smooth, inamyloid (in Melzer''s reagent with a slight reddish brown tint), yellow, cyanophilic, with thickened walls, spore print brown; BASIDIA 4-spored, 15-20 x 4-5 microns (sometimes longer up to 40 microns with prolonged base), clavate, with basal clamp connection, new basidia "as a rule formed not from the basal clamp but opposite to it, forming a characteristic subbasidial hyphae [sic] with lateral hooks marking the sites of earlier basidia"; CYSTIDIA none; HYPHAE monomitic, "thin-walled or in the subiculum slightly thick-walled", with clamp connections and anastomoses; subhymenial hyphae 2-3 microns wide (swelling in KOH), richly branched, "some hyphae with peculiar bands or rings at irregular intervals, sometimes also with capitate projections looking like conidium formation but evidently something else", deviating clamp connections often seen - ampullate or with wide ansiform [handle-like] clamp connections; subicular hyphae normally 3-5 microns wide, not swelling, "provided with a sparse fine-grainy encrustation", with scattered clamp connections and branches, "forming a loose context without interhyphal substance", (Eriksson), SPORES 3.5-4.5(5) x 1.5-2(2.5) microns, short-oblong, in profile cylindric or tapering apically to reniform [kidney-shaped], some with 2 droplets, smooth, IKI-, colorless to pale yellowish, quickly distinctly blue in lactic-blue, slightly thickened, spore print distinctly yellowish or olive-yellow on paper and pallid on glass slides; BASIDIA 14-20 x 4-6 microns, "clavate, often with the basal 5 microns flared"; CYSTIDIA none; HYPHAE monomitic; "subhymenium about 30 microns thick with hyphae closely woven"; context hyphae 2-5 microns wide, "loosely woven to relatively closely packed, branching frequently" and often at a clamp connection, "with large clamp connections, thin-walled, anastomosing", "often incrusted with amorphous, yellowish, resin-like deposits", (Ginns(12)), SPORES 3.5-4.5 x 1.3-1.8 microns, cylindric, smooth, inamyloid, yellowish, cyanophilic; BASIDIA 4-spored, 18-24 x 3-4 microns, narrowly clavate, with basal clamp connection; CYSTIDIA none; HYPHAE monomitic, 1.5-3.5 microns wide, "branched with anastomoses and short outgrowths", some hyphae swelling in KOH, some septa with large medallion clamp connections, according to the literature sometimes with conidia-like offshoots and band-like hyphal thickenings, but these not seen, (Breitenbach)
Notes:
Pseudomerulius aureus has been found in BC, WA, ID, AB, MB, NB, NS, ON, PQ, AL, AZ, CA, CT, GA, IN, LA, MA, MD, ME, MI, MN, MT, NC, NH, NJ, NM, NY, PA, SC, VA, and VT, (Ginns(5)). It has also been found in Denmark, Estonia, Finland, Norway, and Sweden, (Eriksson), Switzerland, (Breitenbach), and Mexico, Austria, France, Italy, Poland, USSR (Europe), India, Japan, and Russia (Siberia), (Ginns(12)).

Habitat and Range

Habitat
on decayed, barkless wood, also on old wooden fences, in north Europe on conifers but reported by Bourdot & Galzin from hardwood, (Eriksson), on Picea (spruce), Pinus (pine), Pseudotsuga (Douglas-fir), Tsuga (hemlock); associated with a brown rot, (Ginns(5)), on wood and bark of conifers, particularly Pinus, collected principally in August and September, rarely in June and November, in southern US and Mexico from December through June, (Ginns(12)), on the underside of dead barkless wood of conifers, especially Pinus; fall-spring, (Breitenbach), all year (Buczacki)