Catapyrenium psoromoides  

Thallus squamulose. Squamules to 3 ( rarely to 4) mm diam. and (150 -) 200-300 (- 350) µm thick, dispersed to contiguous or partly imbricate, ± divided, often somewhat elongated especially at the periphery, loosely attached or slightly ascending at the apices; upper surface dull greyish or greenish brown to fawn; distal parts of squamules often with grey-violet pruina in defined patches; lower surface non-corticate; the upper cortex indistinct, 10-30 µm thick and with an inconspicuous epinecral layer, the medullary layer gradually merging into the dark hypothalline tissue of interwoven rhizoidal hyphae. Algal partner chlorococcoid.
Anamorph: not known.
Teleomorph: ascomata perithecia, 150-200 µm diam., moderately frequent, fully immersed, visible as black dots on the upper surface of the thallus, the peridium ca 20 µm thick, pale or slightly brownish, more strongly pigmented in the ostiolar region, lacking an involucrellum. Interascal tissue absent, the ostiole lined with periphyses. Asci 55-65 x 13-15 µm, clavate, thin-walled, not fissitunicate, not blueing in iodine, 8-spored. Ascospores biseriately arranged, 14-18 × 5-7 μm, ellipsoidal to fusiform, sometimes slightly attenuated at the apices, aseptate but sometimes appearing 1-septate due to the presence of oil droplets at the poles.
Chemistry: no lichen products detected.