Haematomma stevensiae

Haematomma stevensiae is a species of bark-dwelling crustose lichen in the family Haematommataceae. It is found on the bark of mangrove trees in tropical coastal areas, particularly in Queensland, where it forms a white to grey-green crust on the tree surface. The species is named after Gweneth Nell Stevens in recognition of her pioneering work on lichens in Australian mangrove forests. Later studies have shown that populations resembling this species also occur in other Indo-Pacific regions, including Japan, Java, and the Philippines, suggesting a distribution extending well beyond its original Australian range....read more on Wikipedia.