Order: Arthoniales       Family: Opegraphaceae Species: Opegrapha vulgata Growth type crustose. Photos: Co. Cork, Ireland. Very variable. Thallus thin, smooth or +/- cracked, white, grey or brownish, often olive-tinged. Slender lirellae to 2.5 mm long, curved, straight, stellate or forming interlocking networks, the discs usually remaining slit-like. Asci 8-spored, spores (15-)20-30(-40) x 2.5-4(-4.5) µm, 4-7 septate. Pycnidia often present, conidia sickle-shaped 9-18 x 1-1.5 or bacilliform 3-5 x 1 µm. Micrographs below. Common throughout Ireland on shaded, smooth-barked trees and on smooth areas of rough-barked trees. Chemical reactions negative. Similar: O. niveotra has shorter discs (to 1mm), worm-like conidia

Micrographs



Opegrapha vulgata March 2010 and April 2012