Family: Monoblastiaceae Species: Anisomeridium viridescens Growth type crustose Photos: On Hazel (Corylus), Dromore, Co. Cork, SW Ireland. N.B. Greenish colour of thallus in photographs caused by overgrowth of algae Thallus usually a pale fawn or whitish stain, sometimes with orange patches caused by Trentepohlia photobiont. Perithecia small (0.1-0.2mm), circular to elliptical, usually scattered. Spores 1-septate, 12-17(-19) x 3.5-4.7 µm, hyaline to pale brown when overmature, constricted at septum and usually biguttulate, upper cell wider than lower. Pycnidia with either macroconidia (9-11 x 2-2.5 µm) or microconidia (4-5 x 1-1.3 µm). Micrographs (spores, macroconidia) below. Thallus negative. Involucrellum brown, K+ dull green. Usually a pioneer on smooth bark of young Hazel twigs but occasionally found on Holly. A mainly 'old woodland' species that now appears to be colonising former Hazel coppices

Micrographs



Anisomeridium viridescens. July 2024