Irish lichens

Arthonia didyma

Order: Arthoniales       Family: Arthoniaceae

Species: Arthonia didyma

Growth type crustose
Photos: Glengarriff woods, Co. Cork, SW Ireland.

Immmersed thallus with small, flat, brown or black apothecia. Spores are 1-septate, 14-17 x 4.5-7 Ám, colourless becoming brown. Pycnidia rare. Microscope photograph below.
Chemical results: Red-brown pigment K+ grey or olive. Epithecium, hymenium and sometimes the hypothecium with orange-red K+ purple-violet pigment

Found on the smooth bark of shrubs and trees (usually Corylus) in unpolluted woodlands

Arthonia didyma

Arthonia didyma

Microscope photograph
Arthonia didyma
Arthonia didyma . May 2012

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