Irish lichens

Incertae sedis

Species: Racodium rupestre

Growth type filamentous.
Photos: Below overhang, acidic rock. Gougane Barra, SW Ireland.

The thallus forms small patches of dark brown or black, +/- felted filaments. Very similar to Cystocoleus ebeneus but the mycobiont hyphae are straight and not entwined or contorted.

Can be locally common in upland areas on shaded, humid, +/- vertical siliceous rocks. Also found below overhangs where it is sheltered from direct rain. Chemical reactions negative.

Identification is very uncertain, photographs are probably of the cyanabacteria Stigonema

September 2009

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