Summary: Features include 1) thin, resupinate growth on wood, 2) an olive to yellow green, smooth to grandinioid spore-bearing surface, with a whitish margin that is often indistinct, 3) amyloid spores that discolor blue or purple in 2-3% KOH, 4) basidia that are narrowly clavate, usually with a median constriction and narrowing at the base, some with pale blue amorphous granules in KOH, 5) a monomitic hyphal system, the hyphae with clamp connections.
Microscopic: SPORES (4)4.8-5.5(6.4) x (3.2)4-4.5(5.4) microns, nearly round to broadly oval in face view, broadly oval and adaxially flattened in side view, appear smooth but some spores "finely sculptured or verrucose" under high magnification such as 2000x, amyloid (moderate blue), pale yellow to colorless in water, deep purple blue in KOH, wall thickened to 0.6 microns; BASIDIA 4-spored, 22-30 x 5-6 microns, narrowly clavate, usually with a median constriction and narrowing at the base, some with pale blue amorphous granules in KOH; HYPHAE monomitic, context hyphae (1.4)2.5-4.5(5.5) microns wide, "loosely woven, often branched, septa frequent, each with single clamp connection", (Ginns(21)), SPORES of Amaurodon species staining violet to dark blue in 2-3% KOH, (Ginns(23))
Notes: Amaurodon mustialaensis has been found in BC, ID, MB, ON, PQ, AZ, IA, MS, NJ, NM, and OH, (Ginns(5)). It has also been found in Finland and Sweden, (Ginns(21)).
Habitat and Range
SIMILAR SPECIES
Amaurodon viridis is similar in gross features and many microscopic characters including amyloid spores that are colored blue or purple in KOH, (Ginns(21) where Amaurodon viridis is referred to as Tomentella viridis Cunn.). A. viridis has warted spores and a typically hydnoid surface, (Ginns(23)).
Habitat
on coniferous wood, especially Abies (fir), Picea (spruce), Pinus (pine), Thuja, occasionally on hardwood, especially Quercus (oak), (Ginns(21)), on well-rotted wood and bark of logs and fallen limbs, decayed leaves, apparently associated with a brown rot, (Ginns(5))