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Order: Arthoniales Family: Roccellaceae
Species: Opegrapha herbarum Photos: Ardnagashel and Macroom, Co.Cork, Ireland. Identified by Andy Acton and John Douglass Thin or inconspicuous pale grey, brownish or olive-green thallus.The small, scattered lirellae are usually simple, less frequently branched. Slit-like discs becoming fully open, occasionally +/- green-pruinose. Pycnidia are very rare. Asci are 8-spored, spores 3-septate, 18-25 x 5-8 µm with thin perispore. Microscope photographs below. Occurs on acid to basic, smooth, often shady bark. Also found on plant stems (especially brambles) and sandstone. Chemical reactions negative. |
Microscope photographs
Opegrapha herbarum March and May 2010