Hildenbrandia rubra (Sommerfelt) Meneghini (Ar/A)

Blood red to brownish or blackish red crusts on rock and other hard substrata. Conceptacles obvious and containing tetrasporangia.

This genetic group has verified records from the upper intertidal to subtidal (4m) from RI to central Labrador, NL, and Europe. This is unlikely to be the true H. ruba, the genus Hildenbrandia has 36 (and counting) genetic species in the Canadian flora rather than the three or four listed (Gabrielson & Lindstrom; Sears 2002). Considerable taxonomic work remains.