Irish lichens

Zwackhia viridis, Opegrapha viridis

Order: Arthoniales       Family: Lecanographaceae

Species: Zwackhia viridis (Opegrapha viridis)

Growth type crustose, graphid
Photos: On Ash. Caha Pass, Co. Cork, SW Ireland.
Identification confirmed by J Douglass

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 Ám. 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.

Opegrapha viridis

Microscope photographs
Opegrapha viridis

Opegrapha viridis
Zwackhia viridis (Opegrapha viridis). January 2012

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