Always take a look at the sticks and limbs that come down from old trees. There’s a lot of stuff going on up there, out of sight, and breakages provide a great opportunity to see what. This piece of an oak has at least two nice lichens on it.
Star Rosette Lichen (Physcia stellaris).
Rosette Lichen (Physcia millegrana).
Both IDs tentative. The chocolate-like disks are apothecia, where the spores are made.
From Sheldrake’s Entangled Life: “In joining forces, the fungal partners are part photobiont and the photobionts part fungus. Yet lichens resemble neither. Just as the chemical elements of hydrogen and oxygen combine to make water, a compound entirely unlike either of its constituent elements, so lichens are emergent phenomena, entirely more than the sum of their parts.”
Sheldrake continues: “The word individual comes from the Latin meaning ‘undividable.’ Is the whole lichen the individual? Or are its constituent members, the parts, the individuals? Is this even the right question to ask? Lichens are a product less of their parts than of the exchanges between those parts. Lichens are stabilized networks of relationships; they never stop lichenizing; they are verbs as well as nouns.”
Sheldrake asks the same questions about animals, since we are also networks combining microbiomes and viral and bacterial parts that originally came from elsewhere. More anon, as the mushrooms expand my mind.
Backyard and Beyond 
Synergy! As always, more than we expected.