Parmelinopsis horrescens

Usually fairly distinctive on acidic bark and lignum and more rarely on siliceous rocks with its shiny narrow grey-white lobes forming neat rosettes, tight against the substrate and usually covered in black-tipped minute rod-like isidia that seem excessively large for the size of the thallus lobes. It looks like a small Parmelia saxatilis with narrow, divided lobes, somewhat truncate at the tips but with, in addition to the oversized isidia an abundance of black cilia growing out from around the bases of and sometimes the tips of the isidia. On account of this well-developed stubble it might not unreasonably called the “Desperate Dan” lichen. It has a C- medulla in contrast to the C+ pink medulla of Parmelinopsis minarum that also lacks cilia. 

Photo: R G Woods