Parmelia saxatilis (L.) Ach. forme corticole
Differs from the saxicolous form of Parmelia saxatilis type by its habitat, tree bark, notably alignment trees in gardens and parks. Isidia numerous towards the center but some specimen almost are entirely covered with isidia, masking lobes and making identification difficult. N.B. Not to be confused with some forms of Punctelia reddenda that may also produce isidiomorphs but greener with a C-, K-, KC-, P- medulla and with the corticolous form of Parmelia sulcata corticolous form that has soralia and not isidia.*
