THALLUS: endolithic
APOTHECIA: dark red, margin thin and not to slightly lighter than disc, 0.3-0.7 mm wide, flat, epruinose
SPORES: hyaline, polarilocular, 11-12.5(17) x 4-5.5 µm, septum 1-1.5(-3) µm
CHEMISTRY: apothecia K+ deep wine red
Worldwide.
Common Name: Granite Firedot Lichen
Endolithic crustose lichen on non-calcareous rock consisting of nothing but scattered to crowded dark red apothecia.
Non-calcareous exposed rocks, typically granite.
Several Caloplaca species are endolithic, however this is the only one with dark red apothecia growing on granite so far as I know.
Other endolithic Caloplaca species include: (not to be considered complete)
C. marmorata on calcareous rock C. fraudens apothecia with conspicuously lighter margins C. approximata apothecia orange C. luteominia apothecia orange C. nashii apothecia orange C. crenulatella apothecia orange
