Crustose lichen

Lecanora marginata is a crustose lichen with a well developed, yellowish white, continuous or cracked-areolate thallus. The prothallus is prominent and is white to bluish gray. Apothecia are immersed and becoming sessile with a black flat to slightly convex disk with a black somewhat persistent margin. Growing on a calcareous sandstone. Picklejar Lakes Trail, Kananaskis Country, 7154July 28, 2011

This particular lichen growing on a tree have a crustose pattern characterized by their flat and tightly-adhering structure. This pattern helps the lichen to adhere to the substrate better and get more nutrients. I think this is not a random event since it is a very common occurence. Evolution and adaptation could have influenced this pattern since lichens that can adhere better will spread more than those which might get dislodged early.

This slow-growing orange crustose lichen was on a rock on Pourquoi Pas Island, Antarctica.

Possibly Porpidia, Lecidea, Buellia or Rhizocarpon (?), So many choices and they might all be wrong! White crustose Lichen growing on a sandstone boulder, Confluence Park, 0254May_13__2009

ID help needed. Crustose lichen growing on a sandstone, Edworthy Park, 0326May_20__2009

Crustose Lichen

Unidentified crustose lichen growing on a glacial moraine boulder. Bebo Grove, Fish Creek Provincial Park, GPS N50 55.667 W114 06.382 0199May_06__2009

My guess would be a Lecidea or Acarospora. The brown one is possibly Acarospora fuscata. These brown and gray crustose lichens are very difficult to ID. Two crustose lichens growing on a glacial boulder at Nose Hill Natural Area, 0374May_27__2009

dry, on telephone pole, Seattle image 2cm across www.anbg.gov.au/lichen/ecology-polution.html: Though sulphur dioxide is very damaging to many lichens some are highly tolerant. In the 19th century when coal was a common fuel the resulting smoke was rich in sulphur dioxide and lichen 'deserts' were typical around industrial centres, with very few species (or even none) to be found in such areas. The crustose lichen Lecanora conizaeoides tolerates high sulphur dioxide concentrations and during…

Unknown white lichen, Lecanora dispersa 'Mortar Rim-lichen' (?) (brown Dots), Caloplaca fraudens (?) (orange dots), Acarospora veronensis (?) dark brown), Several crustose lichen growing on a sandstone boulder, Votier Flats, Fish Creek Provincial Park, 3192March_05__2010