Summary:
Features include 1) resupinate growth on wood, 2) a waxy, soft fruitbody that is whitish and smooth, the margin filamentous or not differentiated, 3) spores that are elliptic to suballantoid, smooth, inamyloid, cyanophilic, and colorless, 4) basidia that are 2-6-spored, and obconic to tubular, sometimes constricted, and 5) a monomitic hyphal system, the hyphae richly branched, with clamp connections.

Microscopic:
SPORES 6-9 x 2.5-3(4) microns, narrowly elliptic-subcylindric-suballantoid, smooth, thin-walled; BASIDIA 4-6-spored, 15-26 x 4-6(7) microns, obconic to tubular, sometimes somewhat constricted, with basal clamp connection; CYSTIDIA none; HYPHAE monomitic, 2-3 microns wide, colorless, with clamp connections, richly branched, "few straight basal hyphae", (Eriksson), SPORES 7-8.5 x 3-4 microns, elliptic to cylindric, smooth, inamyloid, cyanophilic, colorless, some with droplets; BASIDIA 2-4(6)-spored, 20-27 x 5-7.5 microns, clavate, with basal clamp connection; CYSTIDIA not seen; HYPHAE monomitic, 1.5-3 microns wide, with clamp connections, "sometimes rather inflated at the septa", (Breitenbach)

Notes:
Sistotremastrum niveocremeum has been found in BC, ON, PQ, AZ, FL, IA, MA, MD, MO, NY, PA, RI, VA, and WI, (Ginns), as well as Denmark, Finland, Norway, and Sweden, (Eriksson), and Switzerland and Asia, (Breitenbach).

Synonyms and Alternate Names:
Corticium niveocremeum Hoehn. & Litsch.
Paullicorticium niveocremeum Hoehn. & Litsch.) Oberw.
Taphrina alni sensu auct. mult. (misapplied name)