Description: forms extensive pinkish to purplish chalky crusts in intertidal areas exposed to surf action. Due to strong tolerance to sunlight and desiccation and its crustose nature it is extremely successful in occupying high wave energy habitats. P. onkodes performs a critical role in the formation and maintenance of the biotic reefs of Hawaii by providing an actively growing reef rim, allowing consolidation and cementation of reef material to occur in protected shoreward areas or the Porolithon ridge.