Sea Lettuce (Ulva lactuca) is a widespread type of edible seaweed with thin crinkled green fronds that resemble a slightly translucent lettuce when it is submerged, but may appear more as a slimy green mass if washed up on the shore. It is found all over the world and is actually an alga from a family of algae called Ulvaceae.
Having a bland taste somewhat like salty lettuce, sea lettuce is easily found in on coastlines, especially in tide pools or in rocky intertidal areas. It is often found growing on submerged wood, shells, or anything else that may afford it a foot-hold. It can also survive free-floating in protected pools.
Sea lettuce thrives best in areas where fresh water is coming in, such as the mouths of rivers and streams. It also thrives from any other source of fresh water meeting salt water, such as sewage runoff or industrial waste, both bad places from which to gather.
Its color ranges from a light yellowish green to dark green, but it is most commonly a bright green color when underwater, turning dark when exposed to air.
The leaves are easily pulled away, being very thin (only two cells thick) and can be used raw in salads or cooked similar to other greens. They can also replace other types of seaweed, including nori in sushi. The leaves are very delicate, and can turn mushy if over-treated.
Sea lettuce is also used in the aquarium trade, along with other members of the genus Ulva, various of which are sometimes also known as sea lettuce or similar names. It is sometimes known as green laver.
Sea lettuce is highly nutritious. It is also widely used as a medicine in China and other parts of the world. It is sold in fresh and dried form, as flakes, powders, and other forms. It is frequently used in cosmetic and personal care products like soap, lotion, shaving lotion, shampoo, bath soaks, skin treatments, eye creams, makeup remover, etc. In addition, it is used in animal feeds and as a component in fertilizers.