The crustose,
thallus is wide (although neighbouring lichens will often coalesce to form larger patches), with a greenish-yellow to whitish or greyish-yellow colour. The main identifying field characteristic of
Caloplaca bartlettii are its densely aggregated, mostly apothecia. Microscopically, another characteristic of the lichen are the large
bermaguina-type oil droplets in its
paraphyses.
Parietin is the major
lichen product that occurs in the species. ==See also==