Summary:
Features include tiny, stemless, black, spherical cups erumpent from wood, tearing open by several irregular teeth, the spore-bearing surface deeply concave and gray. Triblidium spp. have large spores with both transverse and longitudinal cross-walls. The accompanying photographs were from a BC collection on the bark of a dead Quercus garryana branch. The exterior would be hard to describe as smooth as given by the description below derived from Dennis(1) - it is possible that another species of Triblidium or related genus is represented in the photographs.

Microscopic:
spores 30-48 x 12-20 microns, broadly elliptic, colorless or slightly yellowish, "with a thick outer wall, about seven to nine cross walls, each locule further subdivided by up to three longitudinal walls", asci 4-spored, up to 270 x 25 microns, clavate, "thick-walled, rounded above, contents deep red in iodine, no blue reaction", spores uniseriate in ascus; paraphyses "slender, forked near the tip, colourless"

Notes:
The accompanying photographs were from a BC collection. Dennis(1) is listing it from the United Kingdom (as rare).

Synonyms and Alternate Names:
Tomentellina fibrosa (Berk. & M.A. Curtis) M.J. Larsen
Zygodesmus fibrosus Berk. & M.A. Curtis