I found these growing on dead, rotting wood the other day. The biggest ones were probably half a centimetre wide. I hauled out Mosses, Lichens and Ferns of Northwest North America (Vitt, Marsh, Bovey), which I’ve found a lot of lichens in, but nothing seemed to match these.
As you can see, they’re white with ochrish tinting inside, and like nothing so much as little cups or pots. I haven’t a clue what they are. Any ideas?