Algae
Algae
"Algae" is a term of convenience for all the "seaweeds", but many  microscopic entities are also lumped in - and 3 billion years of confused  history. It used to be simple to say "Algae are not plants", but that is now  highly controversial. Green and Red algae are now included in clade Archaeplastida, sort of Plantae sensu lato (plants viewed  broadly), with red needing a bit more "lato" than green.  Brown algae are  still safely not plants, but even that could change. Fortunately we can go  ahead and eat them without waiting for all the confusion to be resolved.
I include Cyanobacteria on this page. They are no longer classed as algae,  though still called "blue-green algae" by the health food industry (a more  marketable designation than "pond scum"). Cyanobacteria are the  sole generators of atmospheric oxygen, on their own or symbiotically  inhabiting (in simplified form) the chloroplasts of both plants and algae.  
Fat Choy - Black Moss
Seaweeds were gathered from the shore by our pre-human ancestors  for use as food, and we continue to eat them today. They provide important  minerals, particularly iodine, which can be in short supply from other  sources. Besides being eaten as vegetables, algae and cyanobacteria are  major feedstocks for the food processing, dietary supplement and medicinal  industries.
Very few sea vegetables are toxic, but some are. Cyanobacteria and  single celled algae can be highly toxic, and increasingly infest our  oceans due to climate change and human pollution.
  -   class Phaeophyceae of division Heterokontophyta of    clade Chromista
The brown algae belong to division Chromista and are quite  different from other seaweeds, more closely related to diatoms,  downy  mildew and other microscopic life forms (See Note-A2 ).  They do have oxygen generating chloroplasts, but of a different type  than those of plants.
Kelp - Japanese
  -   [Konbu, Kombu (Japan); Miyeok, Dashima (Korea); Haidai (China): Laminaria japonica (and several other L. species)]
This is edible kelp grown along the coasts of Japan, Korea  and China     - quite different from the giant kelp of California which     is processed rather than eaten directly. The long wide fronds are     dried and packaged for use particularly to make soup stock, but also for     to use as wrappers for various prepared foods. Almost all this kelp used     for food is cultivated rather than gathered wild which explains why there     are so few crunchy critters growing on it.
This kelp is normally sold as flat dried sheets cut from the fronds but     is also sold as narrow cut strips, salted and bagged in the refrigerated     section. In Japan it is also pickled and and served as a snack to     accompany green tea. The photo shows a piece of a frond as dried, and a     shorter piece cut from the end after soaking. Details and Cooking .
Sea Tangle
  -   [Atlantic Kombu, Oarweed; Laminaria digitata]
The name "Sea Tangle" properly belongs to the Atlantic kelp L. digitata, but many packages of kelp found in Asian     markets here in Los Angeles are labeled "Sea Tangle". Actually, this     commercially harvested kelp is closely related to the kombu kelps of     East Asia and can be used similarly, but is not found in the Pacific     at all.
The photo, clearly labeled Laminaria digitata, was taken     in the eastern North Pacific (Washington State), so is probably the     very closely related Laminaria setchellii, which is a little     smaller. Both share the common name "oarweed". L. setchellii is harvested from Alaska to California, and some could be sold as     Kombu in Asia, but the name "sea tangle" doesn't apply to it.  
Photo by Leslie Seaton distributed under license Creative     Commons Attribution 2.0 Generic
.
Kelp - Giant
  -   [Macrocystis pyrifera]
Along the temperate western coasts of North and South America, forests of     Giant Kelp provide food and shelter for fish, crustaceans and other sea     life. The greatest kelp forests in the world are off the coast of California     where fronds can grow to 200 feet (60 meters), and in the warm sunlit     waters of Southern California can grow more than 10 inches (25 cm) a day.
California kelp is both an important resource and important to the health     of the marine environment so harvesting kelp is highly regulated here. The     main threat to kelp forests is not harvesting but sea urchins. Order more Uni in your local sushi bar to     help the spiny lobsters keep the sea urchin population under control.
Hundreds of tons of giant kelp are harvested every year for production     of algin, a thickener and stabilizer used in products from toothpaste to     beer to ice cream and to feed farmed abalone.  
Wakame
  -   [Wakame (Japan); Miyeok (Korea); Qundaicai (China); Undaria pinnatifida]
Related to kelp, wakame is a popular seaweed for soups and salads,     particularly in Japan and Korea.  It has a softly crunchy texture and     a pleasant slightly spinachy flavor. Most familiar in the U.S. as dry,     brittle black tangles in plastic bags. It is also commonly available     salted in bags in the refrigerated section of Korean markets.
The photo specimens are dried tangle (center), salted tangle     briefly soaked (lower right) and a single piece from the salted tangle     spread out (upper left). This is a short length cut from one side of     the central stem.
Wakame has recently been found to contain a substance that     stimulates production of a fat burning protein, so expect it to become     better known in the West. It has become a troublesome invasive weed     along the coasts of non-Asian countries, so eat up!   Details and Cooking
Cuvie
  -   [Tangle; Laminaria hyperborea]
OK, I'm making a presumption that the contents of the can was     L. hyperborea, because that's the kind of kelp they have up there     around Russia. The paper compliance label stuck to the bottom just     said "Laminaria" - everything else on the can was in Russian.
The kelp strips were mild with a pleasant flavor, probably it's     used on the zakuska table. Clearly the Russians didn't quite     understand American labeling law, because the compliance sticker     listed Laminaria last. Ingred: Laminaria, vegetable oil, onions,     vinegar, salt, sugar, garlic, coriander, pepper.  
Left photo by Sergey S. Dukachev Distributed under license     Creative Commons Attribution-ShareAlike 3.0 Unported , Right photo © cg1
.
Arame
  -   [Eisenia bicyclis]
This seaweed is popular in Japan where it may be served alone, mixed with     other seaweeds in a seaweed salad, used as a garnish or included in many     kinds of dishes. It is normally sold dried, and takes a very short     soaking cycle before it is usable. It has a light semi-sweet flavor and     is high in calcium, iodine, iron, magnesium, other minerals and vitamin     A.  
Illustration copyright expired
Hijiki
  -   [Hijiki, Hiziki (Japan); Gulfweed (US); Hai zao (China); Sargassum fusiforme]
This seaweed is found along the coasts of China, Korea and Japan, but     also along the Atlantic coast of North America. Used as a sea     vegetable in Japan, it was brought to North America by the Michio     Kushi Macrobiotic movement. and it is now fairly common in Japanese     restaurants here. It is imported from Japan, China and Korea in dried     form. Hijiki is also used to color Konnyaku Jelly . This seaweed is     now cultivated along the coast of China and the     Korean coast facing China.
Hijiki is high in dietary fiber and a number of important minerals,     particularly iodine, calcium and magnesium, but it is also high in     inorganic arsenic which     has resulted in cautionary pronouncements by a number of governments,     including the US Department of Agriculture. The arsenic content is not     likely to be dangerous in the quantities consumed in normal culinary     usage, the warnings being mainly for "health nuts" who tend to overdo     "healthy" things. As shipped it is black and very tough, so needs     long soaking and cooking to be edible. It has a nutty flavor which     is enjoyed in soups and vegetable dishes.  
Illustration by Kontaro Okamura, copyright expired
.
Bladderwrack
  -   [Fucus vesiculosus]
Bladderwrack is used mainly as a food flavoring and additive, and as a     medicinal, particularly for iodine deficiency and certain female     problems.  
Photo by Stemonitis distributed under license Creative     Commons Attribution-ShareAlike 2.5 Generic .
.
Nori
  -   [Laver       (Europe), Nori (Japan), kim, gim (Korea), Porphyra yezoensis and P. tenera, sometimes other species]
This algae is farmed intensively in Japan, Korea and China. Once harvested     it is shredded and made up into paper-like sheets very much the way handmade     paper is made. These sheets are lightly toasted which turns them green.     They are used as a wrapping for sushi and as a garnish and as a flavoring     in soups.
In Wales similar algae is used to make Laverbread (Bara Lawr)     by boiling the seaweed, then mixing it with oatmeal and frying it. In     the British Isles it is gathered wild in Wales and Scotland rather than     being farmed.
Red Algae is high in protein, iron and iodine as well as containing     significant amounts of vitamins B2, A, D and C.
Red Tosaka
  -   [Tosaka-nori (Japan); Jiguancai (China lit "cockscomb vegetable"); Meristotheca papulosa]
This Indo-West Pacific algae is popular in Japan as an appetizer or     salad and is also popular in Taiwan. Note that in Japan there are green     and white seaweeds also called "Tosaka" and similarly used.  
Irish Moss
  -   [Carrageen, Chondrus crispus]
Found along the Atlantic coasts of North America and Europe in the     intertidal and subtidal zones, this branching and generally reddish or     purplish seaweed grows to about 9 inches long, It can turn green in strong     sunlight. Similar species are found and harvested off Korea and Japan.
Irish moss is harvested as a source of carrageenan. This substance is     used as a thickener for soups and to make jellies. Industrially it is used     as a thickener and and stabilizer in ice cream, luncheon meats and other     processed foods and also for fining beer and wine. It has a long history     of medicinal use in Europe as well.
Irish moss is always harvested wild, with Canada the major harvester at     about 10,000 tons per year followed by France at about 1,260 tons per     year.  
Illustration from Koehler's Medicinal-Plants, copyright     expired.
Sea Lettuce
  -   [Green Laver, Ulva lactuca and other species]
Sea lettuce is found in tidal and near tidal seawater worldwide, generally     anchored to rocks or other algae. It is eaten raw in salads and cooked in     soups, particularly in Scandinavia, Great Britain, Ireland, China, and     Japan.
Sea lettuce is small, generally around 6 inches long but can grow to     three feet. It is almost transparently thin and consists of a single     frond anchored at one point. It may be ruffled or somewhat divided,     generally resembling the lettuce leaves after which it is named.
Most sea lettuce is gathered wild as it grows prolifically wherever     there are sufficient nutrients, but some is farmed.  
Sea Grapes
  -   [Green Caviar; Latu Arusip, Ar-arosep, Arosep (Philippine); Latok       (Malay); Umi-budo (Okinawa); Nho bien (Viet); Caulerpa lentillifera]
This seaweed is now successfully farmed in the Philippines, where it     is liked raw with vinegar as a snack, or in a salad with chopped     onions, tomato and a dressing of fish sauce and vinegar. It is     eaten similarly in Okinawa, Japan. Known to be high in iodine, it has     a light pleasant seaweed flavor and a satisfying crunchiness when     bitten. The stems are tough and stringy, but small and entirely     tolerable (swallow them, you need more fiber anyway).
The photo specimens were packed in salt,     sold at a local Philippine market for 2015 US $4.99 for a package     weighing about 4 ounces. About half the weight was in salt, but when     the seaweed is rinsed and re-hydrated it'll probably weigh about the     same. We have included our ubiquitous red kidney bean for scale.
Sponge Seaweed
  -   [Ch'onggak (Korea); Codium fragile]
This coastal seaweed is found worldwide, even on the coast of     Antarctica. It is a siphonous alga, meaning its round branches are     composed of a tangle of near microscopic filaments, each filament     being a single multinucleate cell. This accounts for its spongy     texture. Its branching fronds grow up to about 12 inches long.
This seaweed is used in various skin rejuvenation products, but     in Asia, particularly Korea, it is used for food, particularly as     a flavor and aroma modifying ingredient in kimchee. It has a     distinctive aroma compared to other seaweeds.   Details and Cooking .  
Photo by Flyingdream contributed to the Public Domain
.
Chlorella
  -   [Chlorella vulgaris of class Trebouxiophyceae]
This single celled algae was, in the 1940s and 1950s expected to, by     now, be one of the most important food crops in the world. This did not     happen for a number of reasons. Production proved far more expensive than     expected, it proved entirely indigestible unless its cell walls were     broken down by processing, it proved difficult to make anything from it     that you'd actually want to eat, and methods were found to greatly improve     output of conventional agricultural products.
Today chlorella is sold mainly as a health food supplement. It has     been found effective at removing toxic heavy metals and dioxins from the     body. It is also thought effective for treating radiation poisoning,     reducing blood pressure and cholesterol, and improving immune function,     though these claims are not without contention,  
Drawing     of Chlorella regularis believed to be in the public domain.
Wila
  -   [Bryoria fremontii of family Parmeliaceae]
This lichen grows in hair-like clumps from tree branches, but is     not parasitic. It inhabits the Mountain West of North America from     the south of Alaska almost to Southern California. Some also grows     in Russia and northern Europe. It was an important food for Native     Americans and is still occasionally eaten as a traditional food. Details and Cooking .  
Photo by Millifolium distributed under license     Creative Commons Attribution-ShareAlike 3.0 Unported
.
Rock Tripe
  -   [Iwatake (Japan); Seogi (Korea); Umbilicaria esculenta of     family Umbilicariaceae]
This fungus grows on rocks in East Asia, including Korea,     China and Japan. It is edible if properly prepared. In Korea it is     often pan fried with pine nuts, and in Japan used for tempura. The     photo is actually U. americana, but it's closely related and looks     pretty much the same. Details and Cooking .  
Photo by Daderot contributed to the Public Domain
.
Spirulina
  -   [Arthrospira]
Spirulina is the commercial name for Arthrospira, a     Cyanobacteria that forms into spiral threads that can be harvested as     pond scum. Spirulina proper is a different bacteria and is not used for     food.
This algae was a significant nutrient for the Aztecs and still     is for some African tribes, but its commercial potential has been     overblown. Wild, unsupportable claims by health food purveyors     have brought heavy fines in California, but the claims continue.     This is not to say it is not nutritious, it is, containing a fairly     balanced protein, many vitamins, minerals and nutritional pigments,     as well as fatty acids
The problem here is that all these nutrients can by obtained at     much lower cost from other sources. Promoters haven't been able to     get spirulina accepted as a general food either, because it looks bad,     tastes bad and can be heavily contaminated with insects, copepods     (tiny crustaceans) and worse - It's grown in open ponds.
Spirulina has been promoted to ethical vegetarians as a source of     Vitamin B12, which they desire to get from non-animal sources (of which     there aren't any in nature). It does contain a significant amount of     a form of B12 not usable by the human body, but any usable B12 in     Spirulina appears to comes from insect and copepod contamination     (animals, in other words). The more contamination the more B12.  
Photo by Joan Simon distributed under     license Creative Commons Attribution-ShareAlike 3.0 Unported
.
Fat Choy - Black Moss
  -   [Hair Moss; Fat Choy = "Hair Vegetable"; Nostoc       flagelliforme]
Not actually a moss, this land dwelling cyanobacteria forms long strands     that look like hair. It is harvested in the Gobi Desert and the Qinghai     Plateau, but harvesting has been restricted due to resulting erosion. Due     to increasing cost, sellers have responded in the time honored Chinese     way - by adulterating the product. Real Fat Choy is dark green - the     adulterant strands, made from starch, are usually black. Real Fat Choy     will stand up to over 30 minutes of simmering, but adulterant strands     will disintegrate.
The photo specimen skein was purchased from a large Asian market in     Los Angeles. It was 16 inches long and folded over, weighed 3-5/8 ounces     (100 grams) and smelled like drying grass. Individual hairs are no thicker     than human hairs, but are actually made up of many microscopic strands.     For nutrition and possible health consideration see Details and Cooking .