Order: Arthoniales       Family: Lecanographaceae Species: Zwackhia viridis (Opegrapha viridis) Growth type crustose, graphid. Identification confirmed by J Douglass Photos: On Ash. Caha Pass, Co. Cork, SW Ireland. Forms small patches of thin or inconspicuous, brownish or olive-green thallus. The small, scattered apothecia are short and +/- rounded and 'button-like' with a narrow, slit-like disc. Asci 8-spored, spores (8-)11-15 septate (with a perispore), 23-60 x 6-9 µm. Chemical reactions negative. Microscope photographs below. Found in SW Ireland, usually on the shaded bark of young Hazel, Holly, Oak and salix in old woodlands. Zwackhia sorediifera (O. sorediifera), is the sterile counterpart, with soralia C+ pink-red, K-, KC+ red, P-, UV- (gyrophoric acid, ± unidentified UV+ red pigments)

Microscope photographs



Zwackhia viridis (Opegrapha viridis). January 2012