Verrucaria ditmarsica Erichsen ?

Washington: Skagit County: Northwest part of Fidalgo Island. Elev. 9 ft.
48° 30' N, 122° 41' 40" W
Coordinate Source: Specimen label.
Littoral fringe. Slope: 10º. Aspect: north. Substrate: serpentine rock. Additional notes present. Substrate: saxicolous.

B. D. Ryan 3987, Aug 17, 1978
WTU, Barcode: WTU-L-017357