In article , wrote...

Does anybody know which species the lichen on the picture is!
http://www.danbbs.dk/~gro_poul/billedkasse.htm

Who told you it is a lichen? It looks like a liverwort to me. Liverworts are
related to mosses & have the same reproductive system, but they look like
pieces of green rubber.

But lichens can be thalloid and rubbery as well. This one, for
example. It is indeed a lichen, and not a liverwort. [But
superficially it's a very liverwort-like lichen].

It clearly looks to me to be a member of the lichen genus
_Peltigera_. Possibly P. canina?

The pale structures are the characteristic fruiting bodies
of the lichen fungus. These lichens are especially rubbery,
perhaps because they contain the blue-green cyanobacterium
_Nostoc_.

IIRC, the familiar species _Peltigera canina_ or "dog lichen" is
named for its often toothlike fertile bodies at the lobe tips
[these are not always present], but there are other similar
species. [As I recall, early herbalists thought the toothy-looking
lichen ought to be good for treating dog bites and rabies (doctrine
of signatures)...]

http://www.robertthompsonphotography.com/page_77.htm
http://www.nmc.edu/~jmedlin/p_canina.html
http://www.southamptoncameraclub.co....dvanced/62.htm
http://www.nawwal.org/~mrgoff/photoj...8frogpelt.html
http://www.bioimages.org.uk/HTML/P153473.HTM
http://www.bioimages.org.uk/HTML/P163352.HTM
http://www.rook.org/earl/bwca/nature...peltigera.html
http://www-biol.paisley.ac.uk/resear...izontalis.html
http://www-biol.paisley.ac.uk/resear...mbranacea.html
http://www-biol.paisley.ac.uk/resear...ritannica.html
http://www.floraislands.is/latflora.htm

cheers