Irish lichens

Opegrapha vulgata

Order: Arthoniales       Family: Roccellaceae

Species: Opegrapha vulgata

Growth type crustose.
Photos: Co. Cork and Co. Waterford, Ireland.
Identification of specimen in lower photo confirmed by J Douglass

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. Disc usually remains slit-like. Small black pycnidia are often present. Microscope photograph below.

Common, widespread throughout Ireland on shaded, smooth-barked trees. Also found on smooth areas of rough-barked trees.
Chemical reactions negative.

Similar: O. niveotra. Shorter discs to 1mm. Basic-barked trees.

Opegrapha vulgata

Opegrapha vulgata

Microscope photograph
Opegrapha vulgata
Opegrapha vulgata March 2010 and April 2012

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