It’s not uncommon to see the two growing together, but I agree in this case that the two groups seem to be pure. I personally find L. vulpina (or L. lupina but that’s another problem and the species isn’t even “officially” published yet) much more common in southern California.

I uploaded two more photos of that same branch, but I don’t know if they will help much. I’ll split them into a separate observation if it is different.

When I found them, I just thought some had fruited and others hadn’t, so I’ll have to look more carefully next time. I don’t know anything about identifying lichen though.

Edit: after reading the descriptions and looking at the observations for both species, I split them into this observation 94634. Most of the ones here were collected off the ground and grouped together, so they are probably mixed. Oops!

See image 218609. No apothecia and I might see soredia.