Summary:
Features include tiny, nearly spherical fruitbodies that open to become urceolate to expanded, the exterior reddish brown or ochraceous brown to black, slightly furfuraceous, and more or less longitudinally striate, the spore-bearing area pale grayish, stem absent, growth on birch, and microscopic characters including asci that begin with 8 thread-like spores but these spores break into many smaller spores.

Microscopic:
spores 54-75 x 2.0-3.0 microns, soon fragmenting into short cells about 5-9 x 2-3 microns, cylindric to elliptic, colorless, these budding off minute spores about 2.0-3.0 x 1.0-1.5 microns, cylindric to allantoid, colorless; asci (80)90-120(130) x (6.0)7.0-8.0(9.0) microns, at first 8-spored but becoming multispored by fragmentation and budding, cylindric to cylindric-clavate, tapering in lower part to a slender stem, pore blue with iodine; paraphyses 1.5-2.0 microns, filiform [thread-like], colorless, septate, simple or branched, "the tips not or very slightly swollen, not forming an epithecium"; conidia (8)10-20(25) x (1.5)2.0-3.5 microns, "elongate-fusiform to subfiliform, pointed at ends, straight or slightly curved, sometimes slightly sigmoid", colorless, mostly 2-celled, occasionally 4-celled; conidiophores 10-35 x 2.0-3.0 microns or longer, cylindric-subulate, colorless, septate, simple or branched; microconidia 2-3 x 1-2 microns, elliptic, colorless, 1-celled

Notes:
There are four collections from BC at the Pacific Forestry Center determined by A. Funk. Collections were examined from ON, Germany, and Latvia, (Groves).

Synonyms and Alternate Names:
Corticium praetermissum P. Karst.
Hyphoderma praetermissum (P. Karst.) J. Erikss. & A.