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

Summary:
Features include flat growth on recently fallen conifers with bark attached, ivory white pores, an ivory white margin that is finely tomentose and often concentrically zoned and fringed, and microscopic characters including cylindric to slightly curved spores measuring 5.0-7.5 x 1.5-2.0 microns, and abundant incrusted, thick-walled cystidia. It is generally rarely collected, but rather common at Priest Lake ID, (Gilbertson). The description derived from Gilbertson(1).

Junghuhnia zonata has been found in BC, WA, ID (type location), CA, MT, and NM, (Gilbertson).

Cap:
growing flat on wood with bark still attached, spreading out up to 6cm, easily separated, drying rigid, margin up to 2cm wide, "sterile, ivory white, finely tomentose, often concentrically zonate and fimbriate"

Flesh:
subiculum less than 0.5cm thick, tough-fibrous; ivory white, not zoned

Pores:
1-2 per mm, angular, with thick entire walls that become torn; ivory white when fresh, drying pale tan; rough; tube layer up to 0.4cm thick, colored as subiculum and continuous with it

Taste:
slightly rancid

Microscopic:
spores 5-7.5 x 1.5-2 microns, cylindric, "slightly curved to distinctly allantoid", smooth, inamyloid, colorless; basidia 4-spored, 14-30 x 5-7 microns, clavate, with basal clamp; cystidia abundant, 40-70 x 8-14 microns, narrowly conic to subulate [awl-shaped], thick-walled, incrusted at top to almost completely; hyphal system dimitic: subiculum generative hyphae 2.5-5.5 microns wide, "thin-walled, occasionally branched, with clamps", subiculum skeletal hyphae 2.5-7 microns wide, colorless, thick-walled, rarely branched, nonseptate, trama hyphae similar with generative hyphae more prominent