Summary:
Postia balsamea produces a white fruitbody that is bracket-like, or flat with the pore surface exposed and bent outward to form a semicircular or elongated shelf-like cap. It fruits on living conifers. Microscopically there are fusoid cystidioles, typically embedded, sometimes rare, and spores measuring 3.5-4.5 x 2.5-3.0 microns. The description is derived from Gilbertson(1) except where noted.

Odor:
pleasant, nut-like

Taste:
slightly resinous

Microscopic:
spores 3.5-4.5 x 2.5-3 microns, oblong to short cylindric, smooth, inamyloid, colorless; basidia 4-spored, 15-20 x 4-4.5 microns, clavate, with basal clamp; cystidia numerous to rare, embedded or rarely projecting, 11-22 x 5-7 microns, fusiform, non-incrusted to apically crusted, with basal clamp; hyphae monomitic, hyphae of context colorless in KOH, thin-walled to thick-walled, with clamp connections, some with frequent branching 2-3 microns wide, others with frequent branching, rather long, nonseptate, thick-walled fragments frequently present, 3-7 microns wide, (Gilbertson), cystidioles 11-22 x 5-7 microns, fusoid, typically embedded, sometimes rare, (Ginns)

Spore Deposit:
white (Buczacki)

Notes:
Postia balsamea has been found in BC, WA, OR, ID, AB, MB, NB, NF, NS, ON, PQ, SK, AZ, CA, MI, MN, MT, NC, NH, NM, NY, PA, TN, WI, and Europe, (Gilbertson).

Synonyms and Alternate Names:
Discina larryi McKnight
Discina leucoxantha Bres.