Rhizocarpon diploschistidina McCune  

Mycobank MB 516796

Thallus areolate, very pale yellowish tan to an intense fluorescent yellow, forming small yellow mounds of areoles on Diploschistes; areoles first appearing as a yellowing surface of the Diploschistes, later protruding as a convex mound with a diffuse margin, ultimately forming discrete but contiguous areoles; apothecia black, lacking a thalline margin; to about 1 mm diam, developing centrally or marginally on the areoles, circular to irregular in outline, becoming compound or confluent; spores dark brown, 16-18 x 7-8 µm , mostly 4-celled (occasionally more or less), the septation and outline often slightly asymmetrical or irregular; epihymenium dark brown; hymenium with POL+ granules; hypothecium dark brown. Secondary chemistry: rhizocarpic acid (lecanoric and diploschistesic acids also detected by TLC in two of three specimens, but these are presumably from the host); cortex P–, K–, C–, KC–, UV+ orange; medulla P-, K-, C-, KC- or KC+ pink (from underlying Diploschistes?), IKI– or partly IKI+ bluish (from underlying Diploschistes?), UV–.