Dusty lemon crust

Appearance

It is a crustaceous species with lobed margin on calcareous rock. The thallus is pale yellow to orange-yellow with narrow, frosted lobes, which can vary in width and length from half a millimeter to one by two millimeters. Soredious in the middle. Apothecia are rarely present. If present, these are orange with a yellow border. It turns red after reaction with potassium ions.

The dusty lemon crust resembles the lobed yellow crust (Candelariella medians), which is all sored in the center and never orange in color.

Microscopic features: The ascospores are hyaline, ellipsoidal and measure 12.5-15.5 x 5.5-7 µm.

Distribution

It occurs in Europe and North America.

Habitat

It occurs on stone, especially basic stone, such as concrete, cement, brick, limestone, fences, bunkers, pasture posts and paving stones. Also on limestone of dikes and rarely on basalt and granite.