Forming yellowish to dark brown tufts of filaments from 2-20 cm tall (Image A), this species is characterized by a notable decrease in thickness from the main axes to the lateral branches (Image B). Possibly confused with Pylaiella spp., this and other species of Ectocarpus are different in their ribbon rather than discoid plastids (Image C) and their terminal rather than intercalary production of reproductive structures (Image D).
We have genetically verified records from the mid intertidal to subtidal depths of 20 m with thalli growing on various hard substrata and other algae, which range from RI to NL. There is unequivocally a greater biogeographical and ecological range in the NW Atlantic and Arctic than accounted for in our collections. We have one verified record from British Columbia, which awaits confirmation. Furthermore, the genus Ectocarpus awaits taxonomic study in Canada with more genetic groups uncovered than currently recognized species (Sears 2016; Gabrielson & Lindstrom 2018).
Image A. Specimen subtidal (2 m) at New River Beach, NB (GWS039127).
Image B. Laterals notably thinner than bearing axes (GWS039127).
Image C. Distinct ribbon shaped plastids with obvious pyrenoids (GWS039127).
Image D. Terminal production of a plurilocular structure (Pointe du Chêne, NB; GWS32389).