Imagine being in the water when the waves come rushing back.

Rockweed is slippery and flexible, going “with the flow” of the water and resisting damage. But moving water can batter anything loose against anything hard, such as rocks, barnacles, or mussels: Floating up a bit may decrease the battering damage.About as wide as your thumb, only flat, the “stems” that make up rockweed are forked and forked and forked again. The ends have a pair of blunt prongs and are often puffed or inflated. Little rockweed, a different species, is about a third the size of rockweed, with the “stems” being about pencil-wide and flat. Both olive brown, rockweed grows up to perhaps ten inches long, and little rockweed grows up to almost 4 inches long.

Rockweeds come in “male” and “female”; the tiny bumps on the inflated ends of the algae are where gametes develop.

Like other seaweeds, rockweed is habitat and food for a variety of animals: It’s best to leave them where they live.

Oregon is home to two common rockweeds: rockweed and little rockweed, shown here. Not particularly closely related, the two are most easily told apart by size (thumb-wide or pencil-wide) and by the presence of a midrib down the center of the forked branches (rockweed) or absence of a midrib down the center of the forked branches (little rockweed).

About as wide as your thumb, only flat, the “stems” that make up rockweed are forked and forked and forked again. The ends have a pair of blunt prongs and are often puffed or inflated. Little rockweed, a different species, is about a third the size of rockweed, with the “stems” being about pencil-wide and flat. Both olive brown, rockweed grows up to perhaps ten inches long, and little rockweed grows up to almost 4 inches long.

Look for limpets, periwinkles, and other life on the fronds and floats of both rockweeds.