Family Description:
Members of this family come in a wide variety of forms, from cylindrical and branched to flattened blades. Some species have a single axial filament, whereas others have a multiaxial filamentous medulla. What unites these species into a single family is the occurrence of the carpogonium at the end of branch of beadlike cells and similarities in the formation of carposporangia after the carpogonium has been fertilized. All of the species described here have an alternation of isomorphic generations, and male and female reproductive structures usually occur on separate individuals.
Species in this family have unusual cell wall carbohydrates that have been shown to have antiviral properties.

Species description:
One of our most easily identified red algae, Cup and Saucer attaches to bedrock and to stones near the extreme low tideline. The small holdfast carries a thick stipe to 10 cm or more (about 4 in) in length. The stipe is branched, and each branch ends in an expanded, circular blade carried almost horizontally. The blades are moderately thick and reach to 20 cm (8 in) in diameter but are usually smaller.

This alga is perennial, and forms additional stipes and blades each year. When this occurs, however, the secondary stipe and blade both form through the winter, so in summer there is no protruding central stipe on the upper surface of the blade. Also, in this species you cannot see the veins in the blade easily. The gametophytes are dioecious, and male individuals develop a wide yellowish band around the periphery of the blade in late spring when spermatia are being produced and released.

Cup and Saucer is the source of a small organic molecule (possibly a polypeptide) that actively kills the bacterium Aeromonas salmonicida, which causes the disease "fish furunculosis," common in crowded salmon hatcheries. Perhaps in the future this alga will be harvested as a source of this important drug. Another species of Constantinea, C. simplex, contains a chemical, possibly a structural polysaccharide, that inhibits a variety of viruses.

Usually only scattered individuals of Cup and Saucer are seen, but sometimes it is fairly abundant.

Source:  North Pacific Seaweeds

Synonyms and Alternate Names:
Constantinea sitchensis
Fucus rosa-marina