Image 2: It could be Parmotrema perlatum (Huds.) M.Choisy.

I do not see any soredia along the margins, so I think Stefan's answer is more likely.

Picture 1: It could be Peltigera polydactyla (Neck.) Hoffm.

Arvind Singh, without seeing a view of the underside of the thallus and the rhizoids, it's aspirational to go beyond Peltigera.

Both pictures were taken on the same Acer tree in Western Switzerland

Anatomical and chemotaxonomical study is needed to confirm the identity.

Thank you to all the researchers who answered my question. The clear conclusion is thut simple pictures are not enough to identify lichens. Sampling and lab identification or series of detailed photos are necessary.

Peltigera sp. is the first one

Picture 2: Cetrelia sp.

It could be Cetrelia cetrarioides

Thanks!!

best

Greg

1. Peltigera canina

Thanks!