Pilayella littoralis, Conferva littoralis

Description: Thallus is yellowish to dark brown and composed of uniseriate filaments to 60 μm diam., richly branched in an opposite rarely alternate pattern (visible microscopically). Cells bearing opposite branches are often trapezoidal in shape.  Reproductive cells are intercalary (not terminal) on branches. This species commonly grows on Rockweed and blooms into large mats, covering its host. Habitat: This ephemeral species is found on rock, other algae, or free floating in the mid intertidal of protected and estuarine habitats. Similar taxa: Ectocarpus, Elachista, Sphacelaria.