Chapsa psoromica Cáceres, Santos de Jesus & Santos Vieira  

Mycobank MB 517751

Thallus corticolous, up to 5 cm diam., 70–100 µm thick, continuous; surface smooth to uneven, olive-green. Thallus in section with well-developed, prosoplectenchymatous upper cortex with internal splitting and irregular algal layer; clusters of calcium oxalate crystals absent. Apothecia erumpent, angular-rounded, 0.4–0.6 mm diam.; disc more or less covered by a narrow pore, flesh-colored and slightly translucent, non-pruinose; proper margin indistinct; thalline margin fissured to lobulate with 3–6 inclined to erect lobules. Columella absent. Excipulum paraplectenchymatous, 30–60 µm thick, yellow; periphysoids present but indistinct. Hymenium 150–200 µm high, strongly inspersed and appearing nubilous grey; inspersion of two types: primary inspersion quickly dissolving in KOH and then hymenium appearing translucent, but secondary inspersion persistent; paraphyses unbranched. Ascospores 8 per ascus, 9–11-septate, 35–45 x 9–12 µm, oblong, with thickened septa and lenticular lumina, colourless, I+ dark violet-blue. Secondary chemistry: psoromic acid.