For more information on the habitat, vegetation, and weather of the area where I made this observation, please see the journal entry for April 28, 2012 here on iNaturalist. This seaweed was common all over the beach. It looks strange when it's flattened out at low tide. This particular specimen was about 7 inches long and was a light brown color. I thought it was sea lettuce at first, but, as was helpfully pointed out to me, this Porphyra doesn't grow in clumps as with this specimen and sea lettuce does.
Porphyra is a foliose red algal genus of laver, comprising approximately 70 species. It grows in the intertidal zone, typically between the upper intertidal zone and the splash zone in cold waters of temperate oceans. In East Asia, it is used to produce the sea vegetable products nori (in Japan) and gim (in Korea), the most commonly eaten seaweed. There are considered to be 60 to 70 species of Porphyra worldwide and seven in the British...
