Description of Pelagophyceae

Stramenopiles, with chlorophyll a/c plastids; marine and usually microscopic, although a few reach macroscopic size; related to the silicoflagellates, pedinellids and Rhizochromulina; vegetative cells are free-swimming flagellates, planktonic coccoid single cells or attached filamentous, palmelloid and sarcinoid masses. With the exception of zoospore formation, alternate life history stages are unknown.