Hi Steve,

It doesn't look quite right to me, although it could be subaridum. Are the edges of the lobes slightly thickened? If so it is not subaridum. L subaridum lobes are usually sort of squared off at the outer edges, not rounded, and these look rounded. Another thing to look at is when dry, are the isidia shiny, with a dimple at the tip? Keep your collection and I can look at it, if you don't figure out what it is.

best, daph

could easily be a Collema. In an xsec, look for a cortex (usually only 1 layer) or look at a surface view and see if you can see a clear pattern of isodiametric cells. good luck!