05 October 2009

Afon Argoed lichens

1. Porpidia macrocara
2. Porpidia tuberculosa
3. Rhizocarpon reductum
4. Baeomyces rufus
Charles & Hilary Hipkin noticed this amazing rock while walking on the Penhydd Trail in Afan Argoed on Saturday. Charles wrote: These are all crustose lichens that grow on acidic rocks. You can find them on any walk in upland areas of the Swansea and Neath Valleys. The reddish stained lichens in the photo are all Porpidia macrocarpa . It produces very large black apothecia and extracts iron from the rock, which gives rise to the red colouration. Rhizocarpon reducrum is somewhat similar but has a black-lined, cracked prothallus with lots of small black apothecia. Both are very common on acidic rocks in the uplands. The plain white lichen (but often with a few apothecia) is Porpidium tuberculosum. It’s an extremely common lichen on acidic rocks, in upland areas and walls and gravestones in the lowlands. Baeomyces rufus has short-stalked brown (or pinkish-brown) apothecia at this time of year which make it very conspicuous. It is called the Brown-beret lichen. It’s not as common as the others, but now is a good time to look for it.

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