A large genus of blade-forming red seaweeds.

Porphyra grows in the intertidal zones of rocky shorelines throughout the world. Though not many are found in either the poles or the tropics, they are mostly concentrated and have the greatest diversity in the cold waters of the temperate regions.

Many species are edible and were a traditional food of coastal people especially in NE Asia. It has many names in the places it is eaten including:

  • laver- England
  • nori- Japan
  • kim- Korea
  • sluckum- North American Pacific Northwest peoples
  • karengo -New Zealand Maori

Currently Porphyra is cultivated in a billion-dollar aquaculture industry by Japan, Korea and the People's Republic of China and is exported globally.

In science, it the focus of physiological research to understand more about its extreme desiccation tolerance. Especially of some of the high-intertidal Porphyra species.