Hi folks with crustose lichen experience - I've spent way too many hours on a small grey Rhizocarpon-ish lichen on chert from the Tombstone Territorial Park in the Yukon Territory, Canada.  Hoping for some advice. 

See the two composite images Haughland 2018-304 in photos. Spot tests, spore measurements, KI results, sections and closeups are in the composites.

The apothecia are lecidiene and appear gyrose/contorted. They are relatively sparse and in clusters. The rim is pronounced, the exciple interior is brown but not carboniferous/black and it's KI-. The first section I did I found the Rhizocarpon-type spores as well as the simple, hyaline spores. All sections thereafter only had the latter. I can't tell how many spores/ascus for the Rhizocarpon-type spores as the 3 spores are all I found.

The central thallus is made of grey verrucae/areoles with low black lumpy material between. As the thallus wraps around the chert it becomes white towards the outer edge and there is a fibrous blueish-grey prothallus at the outer edges in part.  Both the grey and the white verrucae react K+red.

So far I've got two guesses: a Lecidea lactea parasitized by a Rhizocarpon? Or a Rhizocarpon parasitized by a Miriquidica? 

Thanks for any guidance anyone can provide.

Cheers,

Diane