Lecanographaceae Alyxoria culmigena (Opegrapha herbarum) Chemical reactions negative Found on acidic to basic, smooth, often shady bark, also sometimes on plant stems (especially brambles) and sandstone. Occasionally host to Laeviomyces opegraphae Thin or inconspicuous pale grey, brownish or olive-green thallus. Lirellae usually simple, less frequently branched, the discs becoming fully open, rarely pruinose but margins sometimes with green pruina. Pycnidia very rare. Spores 3-septate, 18-25 x 5-7 µm with thin perispore. Septa often thicker by spore wall and 2nd cell usually broadest and longest. Micrograph below Similar: Non-pruinose forms of O. ochrocheila have smaller 3-septate spores, 2nd cell +/- same length as others and evenly thin septa

Microscope photograph



Opegrapha herbarum
Arne, Badbury Rings and Broadstone, Dorset. February 2014, January 2017, 2025