Description: Thallus is dark red, saucer-shaped, with frequently lacerated blades, attached in the middle of their lower side to a branched, cylindrical stipe. Thallus grows up to 20 cm (10 in) tall overall with blades to 30 cm (12 in) in diam. Blades have conspicuous veins on their underside, where tetrasporangial sori develop. This perennial grows a new blade each winter at the end of the stipe that protrudes through the center of the previous year’s blade beginning in late spring. Habitat: This species is found on rock in the low intertidal to shallow subtidal of semi-protected to semi-exposed habitats. Similar taxa: Constantinea rosa-marina.