Leioderma

Leioderma is a genus of lichen-forming fungi in the family Pannariaceae. These lichens form small, leaf-like rosettes that are loosely attached to their growing surface and can reach 10–15 cm across. The upper surface is typically grey-blue in colour and may be smooth or have a fine, cobweb-like texture. The genus contains nine species that are mainly found on tree bark in humid forests, with a distribution centred on New Zealand and Australia but extending to South America and North America....read more on Wikipedia.