Description: Thalli of this species form a carpet of many tiny (up to 8 mm or 0.3 in tall), green, undivided blades. The blades have short stalks basally and are often curved and hoodlike at their tips. Cells are quadrate or rectangular, 5-9 μm long and wide, and not clustered in groups of four or more with spaces between groups of cells. Habitat: The species is found on rock in the high intertidal to above high water mark. It is frequently associated with bird rookeries where guano provides high concentrations of nitrogenous compounds it tolerates or needs. Similar taxa: Prasiola borealis.