Tidepool Tim says,  “Broad leaf kelp looks like a dinosaur kelp plant. They are big, thick, and resemble old weathered horse harness leather. We can find these lodged in the mid-tidal areas as they have torn loose from the seafloor and drifted up the water column.  A close look at the stipe and frond of these specimens will reveal years of growth and evidence of many fouling species living on the plant itself. The blade is very wide - usually 16" or more. The holdfast is very rugged and branching with lots of other creatures lodged in the structure.  Small rocks and large horse mussels seem to serve as the anchor for this marine algae.”