Scoliciosporaceae Scoliciosporum umbrinum Growth type crustose. Chemical results negative Found on a range of natural and man-made sub-strates including +/- basic or acidic rocks, memorials, walls, rusty metal, branches and wood. Variable. Thallus grey-green or dark brownish-black, thin, scurfy and +/- cracked or thick and nodular-uneven. Apothecia frequent, discs blackish-brown, +/- convex, glossy when young with paler, sometimes persistent margins. Spores (15-)20-30(-40) × 2-3 µm, 3-7 septate and twisted. Micrograph below. Similar: Scoliciosporum chlorococcum (spores less curved in asci) and Scoliciosporum sarothamni (sorediate with coiled spores)

Micrograph

Scoliciosporum umbrinum
Photographs: Corfe Mullen, Dorset. March 2025