Diploschistes muscorum is said to begin as a parasite of species of Cladonia. Other lichens which may also be parasitized (or overgrown?) by D. muscorum include species of Stereocaulon and Squamarina. Posting photo in which it seems to be parasitizing Lecidea tessellata. Red arrow indicates area which to me most appears to be replacement rather than overgrowing. (view original size) Perhaps this is commonly observed.
 (Interesting that D. muscorum may begin by using a host’s photobiont, e.g. Trebouxia irregularis, and upon becoming independent switches to a different photobiont, e.g. Trebouxia showmanii.)

Really beautiful photos of Diploschistes muscorum parasitizing Cladonia posted by Amadej Trnkoczy:

https://www.flickr.com/photos/atrnkoczy/39142866980/

https://www.flickr.com/photos/atrnkoczy/39142864130/in/dateposted/

Thanks Bruce. Definitely I’ll look at Lumbsch’s papers.

Going through Diploschistes just now in Microlichens of the Pacific Northwest I notice the distribution of Ingvariella bispora as ”known from Wyoming, s California, and Sanda Cruz Mts (Carlberg 2012)” Attaching some photos of what I think is I. bispora (invading Lecidea?) from Lopez Island, San Juan County, WA. Also note Noble collected it on “HCl- sandstone at a maritime site on Saltspring Island” (not far from Lopez Island). (Don't think I had mentioned this in a previous message to you regarding ranges of some lichens.)