Genus prostrate or erect; flat, deltoid or orbicular;
simple at first, becoming lobed with age; with marginal rows of apical
Species light brown to tan; fan-shaped, kidney-shaped or orbicular blades flat, to 6 cm wide, 1-3 mm thick; erect or decumbant, attached to substrate by rhizoids.
Common in intertidal zone; on rocks, old coral heads,
shells; in moderate to extreme exposure; year round; sparse in late summer.