This lichen is a national BAP species only recently recorded from Wales and not yet included on the Section 42 list.It forms an extensive smooth, soft matt white to mottled pale grey-green thallus that scratches orange as it contains Trentepohlia as the symbiotic alga. Commonly scattered over the thallus are pinkish to orange apothecia discs surrounded by a notched pseudothalline margin that may become excluded.
|Cryptolchia carnolutea on ivy stem (Photo: Ray Woods)||Cryptolchia carnolutea on limestone (Photo: Ray Woods)|
On bark the apothecia are never as sunken as Gyalecta species whilst on limestone Petractis clausa has apothecia more completely covered by the thalline margin and has a pale grey not white thallus.
Recorded on four shaded limestone outcrops in the Merepool Valley within Stackpole NNR on land owned by the National Trust in Pembrokeshire where it was first noted by Bryan Edwards in November 2007. He considered it to be one of the largest populations in Britain. One population was rediscovered in August 2011 by Ray Woods and Tim Wilkins of Plantlife at SR9704393952.