Chapsa thallotrema N. Salazar & Lücking  

Mycobank MB 517753

Thallus grey-olive, smooth to uneven, with dense, prosoplectenchymatous cortex with internal splitting, sorediate; soralia usually numerous but discrete, capitate, finely granular, 1–2 mm diam., white to bluish or yellowish white, strongly contrasting with the surrounding thallus; photobiont layer and/or medulla with clusters of calcium oxalate crystals. Apothecia erumpent, angular-rounded, 1–3(–5) mm diam.; disc exposed, flesh-colored to pink-purple; margin lobulate to recurved, often layered, flesh-colored to beige. Columella absent. Excipulum paraplectenchymatous, colourless; periphysoids present. Hymenium 150–200 µm high; paraphyses unbranched. Ascospores 2–4/ascus, 15–19-septate, 60–120 x 10–15 µm, cylindrical, with thick septa and lens-shaped lumina, colourless, I+ violet-blue (amyloid). Secondary chemistry: stictic acid and satellites (K+ yellow).