PLANTS OF THE SEA 85 



Most red algae are small and filamentous or branched. For that reason they are 

 frequently called "sea mosses." Many genera are much alike and frequently 

 hard to identify. Red algae are most common in temperate to tropical seas. There 

 are 2,500 species the world over. 



Laver, Porphyra, looks like sea lettuce and is frequently epiphytic— found 

 growing on other plants. Like sea lettuce, it is fragile and washes up on beaches 

 or into shallow water. It is found from the subarctic to the tropics and is orange 

 or red to purple in color. It reaches 3 feet in length. Gymnogongrus is a beautiful 

 and striking dark purple alga which looks like a small rockweed. It frequently 

 grows among tropical coral but is also found in the temperate zone. It has a 

 firm or even horny texture. Gigartina has a wide range of habitats from quiet 

 sandy shores to rugged rocks where it must withstand the pounding of a heavy 

 surf. It may be olive to purple or rose-red in color, and the surface is roughened 

 by little outgrowths. The texture is leathery, and the plant may be branched, 

 single, or spatulate in shape. Polysiphonia is very mossy in texture and finely 

 branched. It is commonly only a couple of inches in length but may reach 3 

 feet. The color is a dark purple to brown or black, or even olivaceous. The many 

 species are found from the arctic to the tropics of both coasts, and they grow 

 anchored to rock, wharves, or other plants from the tidal zone to moderately 

 deep water. The Irish moss, Chondrns, is very common, growing on rocks in 

 shallow water. The various species are quite variable, but all are bushy and not 

 over a foot tall, most being only a few inches. The color is a rose- to purple-red, 

 or even with a green tinge, and the distribution temperate. It is a source of 

 industrial chemicals. The dulse, Rhodymenia, gets into fairly deep water and 

 is also found in the tidal zone. It looks like rockweed or Gymnogongrus in its 

 branching and is a pretty, bright purplish red in color. It is of temperate 

 distribution, keeping to deeper waters to the south of its range. Very often 

 species of this genus have little bladelets at the tips of the main blades. Several 

 species reach a length of a foot, but most are smaller. Agardhiella is a treelike, 

 small, branched red alga which is very common on temperate coasts. It is 

 frequently heavily burdened with crustaceans and other animals that live in 

 its branches. 



Several red algae deposit calcium carbonate or lime around themselves. Some 

 of these aid in the building of reefs. CoralUna ranges from the tropical to the 

 temperate zones of both coasts. It is a dull purple or red in color and reaches 

 a height of 6 inches. Bossea is a West Coast coralline alga, which grows on 

 rocks in shallow water. It reaches a little over 6 inches but is mostly much 

 smaller. 



SEED PLANTS: Phylum Tracheophyta 



The eelgrass, Zostera, and turtle grass, Thalassia (^g. 43^, and their close 

 relatives are alone among the truly marine seed plants. They live in sandy, 

 or muddy, quiet shallow waters. The leaves are slender and reach up to 4 feet 

 in length. These plants send out long runners to propagate and bear small 

 flowers and seeds. Many animals such as sea horses and green turtles depend 

 upon these grasses for homes or food. It is unfortunate that because of pollution 

 and parasitic infestation eelgrass has disappeared from much of its former 

 territory. These plants range from the arctic to the tropics of both coasts. 



