Recently encountered what I take to be Cyclohymenia epilithica on many granodiorite outcrops in shade of relatively old 2nd growth forest (western hemlock, douglas fir, etc.), along “trail” to Stegosaurus Butte, 500-600m elevation, above Middle Fork Snoqualmie River, western Cascades of Washington. Photos posted to gallery (best viewed full size). Apparently quite common in the area.
See McCune, Curtis and Di Meglio 2017 New taxa and a case of ephemeral spore production in Lecideaceae from western North America. The Bryologist 120(2): 115-124