Amandinea decedens
Amandinea decedens is a crustose lichen in the family Caliciaceae, first described as Lecidea decedens by Finnish botanist William [Nylander (botanist)|William Nylander] in 1869. It was assigned the name, Amandinea decedens, in 2002 by Juliane Blaha and Helmut Mayrhofer. The name was validly published in 2016 by Blaha, Mayrhofer and John [Alan Elix|Jack Elix]
On coastal rocks, when it is found, it is abundant.