Introduction to the Phaeophyta

Kelps and brown "algae"

The largest of the chromists are the Phaeophyta, the brown algae -- the largest brown algae may reach over 30 meters in length. The rockweed shown at left, Fucus distichous, visible at low tide at the Berkeley Marina in California, is somewhat smaller. Almost all phaeophytes are marine.

Phaeophytes, like most photosynthetic protists, have traditionally been classified as plants. However, phaeophytes are not closely related to land plants; their cells contain different pigments, such as chlorophyll c and fucoxanthin. They also lack the plasmodesmata and starch production of land plants and their relatives.

Like plants and many protists, brown algae undergo a complex life cycle involving alternation of generations. In this picture, you can see a diploid kelp with flat photosynthetic structures, the blades, branching from the stipe, or stalk. The "puffy" regions attached to the blades are receptacles, structures in which the gametes are produced.

Click on the buttons below to find out more about the Phaeophyta.

An excellent source of information about brown algae of California tidepools is available from Sonoma State. The exhibit is called Algae: The Forgotten Treasure of Tidepools.

You can see a view of a kelp forest in an aquarium tank available from the Stephen Birch Aquarium at the Scripps Institute of Oceanography in San Diego, or at the Monterey Bay Aquarium. Check out some of the largest chromists on the planet.

For more on the biology and economic uses of phaeophytes and other seaweeds, visit the excellent Seaweed Information Server maintained at University College Galway, Ireland, including a checklist of phaeophyte species of the British Isles and northern Europe. Or visit the DELTA Project for information on brown algae of California, as well as other algae and marine vascular plants.

For a fuller listing of on-line phycological collections resources, try our Phycological Collections Catalogs Listings.