The members of Phaeophyceae are popularly called brown algae. The brown colour of this group of algae is due to the possession of a pigment called fucoxanthin. There are about 1500 species enlisted in phaeophyceae. Fritsch (1945) divided the whole brown algae in to nine orders: Ectocarpales, Tilopteridales, Cutleriales, Sporochnales, Desmarestiales, Laminariales, Sphacelariales, Dicotyotales and Fucales.
Characteristics of Class Phaeophyceae (Brown Algae):
- Mostly marine, with unicellular or multicellular body.
- Cells are eukaryotic, with special type of excretory granules in vesicles.
- Chief pigments are chloroophyll a and c, beta carotene, lutein, fucoxanthin, dioanthin and violaxanthin.
- Reserve food includes laminarin, mannitol and oils.
- Sexual reproduction is isogamous, anisogamous or oogamous.
- Zoospore formation is common.
- Male gametes are flagellate.
- Flagella are heterokont.
- Life cycle is haplobiotic or diplobiotic, with alternation of generations.