E-Flora BC: Electronic Atlas of the Flora of British Columbia

Family Description:
Members of this family have a single, terminal blade that is divided in some species. The stipe is rarely branched. Blades are smooth or undulate, entire or with holes, of uniform thickness or with a central, thickened region (midrib). Sori develop directly on the blades.

Species description:
On the outer coast, Suction-cup Kelp can be found in the extreme low intertidal zone (although rarely, because it is really a subtidal species). Its highly distinctive holdfast is undivided, forming a large suction cup with somewhat irregular borders. From a distance, it looks something like a plumber's friend pushed firmly onto the rock.

The single, rather rigid stipe is up to 20 cm (8 in) longor more, and 2 cm (0.8 in) in diameter. The dark brown blade is similar to that of Split Kelp (L. bongardiana), smooth or bullate, entire or dissected, and nearly as long and as wide.

Several other species of intertidal Laminaria occur in our area and some of these are difficult to identify because their morphology might depend on the kind of local habitat they occupy. Recent molecular studies have shown that the formerly favored grouping of Laminaria species into simplices (with blades that are not subdivided) versus digitatae (with subdivided blades) is probably not valid.