Prevalent in Eastern North America
Ramaricium polyporoideum often grows flat and spread out (resupinate) on the underside of damp logs, forming a spider web of fungal mycelium. Will also become crust-like on hardwood logs (good example at iNaturalist). Belongs in the family Gomphaceae, which, surprisingly, includes many of the coral and club fungi. Formerly named Corticium polyporoideum. This fungus has some really gnarly tuberculate/nodulose (bumpy) spores. Check out the scanning electron microscope images below.
This collection of Ramaricium polyporoideum was identified by DNA sequencing within the MycotaMap Network. Raw data here.
This image by Stephen Russell shows the crust-like form of this fungus growing on the bark of a sycamore tree. Brown County IN.
Resources:
SEM images of spores at ResearchGate
Images of Ramaricium polyporoideum at iNaturalist