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Nori
Porphyra spp.
Subspecies
There are seven main species which are cultivated mainly in China and Japan.
Statistics
Thalli begin life as uniseriate filaments which are eventually replaced by parenchymatous sheets of cells (1-2 cells thick). Individuals often grow up to 20cm across.
Physical Description
This is a small red alga with an irregularly shaped, broad frond that is membranous but tough. The plant attaches to rock via a minute discoid holdfast. It is greenish when young becoming purplish-red and has a polythene-like texture.
Distribution
It is found worldwide in the higher latitudes.
Habitat
It occurs singly or in dense colonies throughout the intertidal, but most frequently at upper, levels. Nori is highly adaptable to different conditions on the shore.
Diet
It is photoautotrophic, converting light into food energy through photosynthesis.
Life cycle
This species has a very complex life history involving three different life forms. These are so distinct, that until 1949, one of the stages was thought to be a different species of algae.
Reproduction
The characteristic flattened thallus is the gametophyte. This releases gametes which grow into a filamentous from. This in turn releases spores which grow into yet another branched filamentous form which finally releases spores that grow into the gametophyte.
Notes
Porphyra, commonly known as nori, is the most widely consumed seaweed in the world! It's commonly found in Asian food, especially Japanese, which has lead to the huge nori industry in Japan.
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