Phlyctis

Phlyctis is a genus of lichen-forming fungi in the order Gyalectales, and the type genus of the family Phlyctidaceae. Members of the genus are commonly called whitewash lichens. These parasitic lichens typically form very thin, patchy crusts on host surfaces or live almost entirely within their hosts, producing minute fruiting bodies that remain largely hidden beneath a coarse white pruina. The genus is characterised by spores that are densely divided by many walls into a net-like pattern and often have tiny points at their ends. Phlyctis contains about 20 species distributed worldwide, with several new species having been discovered in recent years, particularly from India, Australia, and other tropical regions....read more on Wikipedia.