This perennial kelp is a robust species found in colder regions of BC. It is distinctive for having a discoid (Image A) rather than hapteral holdfast combined with a divided blade (Image B).
Our collections are from northern BC, both the Prince Rupert region and the Haida Gwaii region. They are attached to rock or cobble and range from the low intertidal to subtidal (11 m). Laminaria ephemera Setchell overlaps in range with Laminaria yezoensis, but typically is less robust, has a much smaller discoidal holdfast, is a short-lived annual (sporophyte stage) and typically has a simple (undivided) blade.
Image A. Close up of the discoid holdfast that characterizes this species (subtidal (11 m) on rock, Ramsey Island (N Bay W anchorage), Gwaii Haanas, BC; GWS028472).
Image B. Specimen displaying the typically divided blade growing in the lower intertidal on rock at Ridley Island (south of coal terminal), Prince Rupert, BC (GWS004941).