Sarah Delong-Duhon's Stereum "ostrea"-group key
Bookmarking from the profile info/research of @sarahduhon:
"Easy peasy guide to S. ostrea species complex:
S. lobatum
stains yellow
matted, felted tomentum, individual hairs not seen
develops wide bands, starting at the edge, where tomentum has worn away to show chestnut cuticle
S. subtomentosum
stains yellow
wooly, hairy tomentum, felted in zones
develops some banding
S. fasciatum
no stain
coarsely hairy tomentum
very little banding, cuticle turns black with age
Examples:
S. lobatum (young) https://www.inaturalist.org/observations/125217768, S. lobatum (old) https://www.inaturalist.org/observations/108692953
S. subtomentosum (young) https://www.inaturalist.org/observations/52709545, S. subtomentosum (old) https://www.inaturalist.org/observations/130543895
S. fasciatum (young) https://www.inaturalist.org/observations/125217848, S. fasciatum (old) https://www.inaturalist.org/observations/130543764
"
