Sea Vegetables: edible seaweeds

Seaweeds are plants that grow in or near salt or fresh water. Of the approximately 25,000 known species, only about 40 taste nice, and of these, only a handful are harvested for retail sale. There are four main types of seaweed: green algae (such as sea lettuce) are delicate and grow in shallow waters; red algae (dulse and nori, for example) grow and can photosynthesize in depths up to 250 metres because of their special red pigment; brown algae (arame, hijiki, wakame, and kelp are examples) grow at moderate depths of about 20 metres; and blue-green algae (such as spirulina) are primitive microscopic plants.

[if a sea vegetables has multiple names, then all known names are included on the list]