Pelvetia fastigiata is the scientific name for Rockweed. Rockweed can be found on rocks that get washed by waves in the high tide zone. It is a very delicate plant. Its fronds are very long and sometimes rip of the rock. These fronds can reach up to 35cm long. They are usually green. The Rockweed is a home for many animals like crabs, sea slugs, isopods and sea stars. The Rockweed normally grows in the same area as the sea lettuce, but the difference between the two is that the sea lettuce is very slippery and the Rockweed is not.