Caloplaca herbidella

Recently C. coralliza has been found to be British (Arup & Akelius 2009) with a single record from Levens Park, Cumbria. It occurs also on trees, is very rarely fertile and then with only a few apothecia. Most specimens have a distinct light beige to dark or orange-brown coloured thallus and isidia. The isidia tend to be formed more in discrete coral-like clusters though they may coalesce.  When this happens the crust of isidia frequently cracks into seperate islands or areoles. In C. herbidella such dense turves of isidia are rare and never crack. C. herbidella may also superficially resemble Caloplaca ferruginea, though the latter lacks isidia . Thalli without apothecia can resemble forms of some Porina species though they all tend to occur in shaded or sheltered situations and C. herbidella is a lichen of well-lit pasture woodland trees. Caloplaca chlorina has a darker grey thallus with a blue tinge, and occurs on rock rather than trees. Pertusaria coronata is K+ yellow, Pd+ orange.