Sagenidiopsis isidiata G. Thor, Elix, Lücking & Sipman  

Mycobank MB 517811

Thallus up to 10 cm diam., usually several thalli of different size growing intermixed, rather loosely appressed to the substrate, byssoid, not flaking off, cream-coloured to greyish; in section up to 0.4 mm thick, hyphae 3–5 µm wide, without calcium oxalate crystals. Hypothallus below the entire thallus, byssoid, dark brown to blackish brown, composed of 3–4 µm wide hyphae. Prothallus prominent, up to 5 mm wide, byssoid, composed of interwoven and radiating hyphae, dark chocolate brown. Pseudoisidia numerous, cylindrical, unbranched or sparsely branched, fluffy-felty with projecting hyphae, of same colour as thallus or slightly paler, up to 0.8 × 0.5 mm. Photobiont cells single or in short, irregular threads, 23–31 × 17–25 µm. Ascomata and pycnidia not seen. Secondary chemistry: C+ red, K–, PD–, UV+ white, I–, K/I–; diploschistesic acid [major] and lecanoric acid [minor] (P. & B. v.d. Boom & V. Freire 33413, HPLC by J. Elix).