_MG_3961 lichens on gravestone 1995-2011

_MG_3961 lichens on gravestone 1995-2011

Observation - _MG_3961 lichens on gravestone 1995-2011. Description: Same gravestone photographed in mid july 1995 and Dec 2011 to show change in lichen communities. Is the black one the same species in same place?

Same gravestone photographed in mid july 1995 and Dec 2011 to show change in lichen communities. Is the black one the same species in same place?