Porpidia macrocarpa

Porpidia macrocarpa is a common crustose lichen that occurs on siliceous rocks in exposed places. Although it is most frequent in the uplands in our area, it can also be found at lower elevations where suitable substrates occur. It bears large black apothecia that may be up to 3mm in diameter. The thallus often becomes rust red in colour as a result of the oxidation of iron that it extracts from the rock it is growing on.

Listed as Huilia macrocarpa by Alan Orange in Flora of Glamorgan (Wade et al, 1994).