Arthoniaceae Bryostigma lapidicola (Arthonia muscigena) Growth type crustose Chemical results negative. Photobiont chlorococcoid Usually found on twigs (especially Elder) or tree trunks. Occasional on bryophytes, pine needles, lignum, shaded siliceous rocks and on other lichens. Tolerates suburban conditions. Patches of tiny, irregularly convex, black apothecia on a thin olive-grey or greyish-brown scurfy-granular thallus. Asci are 8-spored, spores 1-septate, 8-12(-14) x 2.5-4 µm. The upper cell is shorter and broader than lower cell which often has a slightly pointed apex. Micrographs below. Similar: Arthonia didyma, photobiont Trentepohlia and wider spores

Micrographs





Bryostigma lapidicola (Arthonia muscigena)
Photographs: Broadstone, Dorset. January 2024