Thallus.
Growing on a moss-covered decaying Western Redcedar stump.
A separate observation for the symbiotic green algae can be seen here:
https://www.inaturalist.org/observations/103833632
Links for my own personal reference:
https://www.mykoweb.com/CAF/species/Lichenomphalia_umbellifera.html
https://ultimate-mushroom.com/poisonous/698-lichenomphalia-umbellifera.html
http://linnet.geog.ubc.ca/Atlas/Atlas.aspx?sciname=Lichenomphalia%20umbellifera
sometimes a lichen infused log puts out Lichenomphalia, but this particular stump was crazy with many square feet of fruiting bodies. They looked a little limp; they may have gotten cold.
Found on decaying hardwood
On decorticated log