Some individuals of this phyla are unicellular, however, the majority are filamentous with coenocytic mycelia. They are also characterized by absorptive nutrition and haplobiontic or diplobiontic life cycles. These organisms reproduce by planogamatic copulation (motile gametes), gametangial copulation, or by somatogamy involving fusion between rhizoids. The asexual spores are called zoospores, which have a posterior, whiplash flagellum. Some produce a rhizoid which anchors the fungus and can be used in the acquisition of food. There are few plant pathogens in this phyla. The most important ones are Olpidium, Synchytrium, and Physoderma.