Groups into Which Plants Naturally Fall 447 



felted mats, buoyed up by entangled bubbles of gas on the surface 

 of still waters; Cladophora, and its relatives, often mistaken for 

 Mosses, those hair-like, net-like, brush-like, fringe-like forms 

 which sway and wave from their moorings on stones in the bot- 

 toms of slow-moving brooks; and certain of the simpler kinds 

 which are enslaved in the meshes of some Fungi to make up the 

 remarkable Lichens. The curious Red Snow, reported by Arctic 

 and Alpine expeditions, and the redness of the Red Sea, famed in 

 geography and biblical history, owe their characteristic colors to 

 certain red stages in the development of simple Green, or Blue- 

 green, Algae. 



Of the BROWN ALGAE the most familiar are the Rockweeds, 

 whose tough branching fronds cover rocks of the beaches where 

 exposed to the swing of the tides; the great leathery Kelps, 

 known to the sailors as "Devil's Aprons," abounding in the 

 seas of the north; and the leafy-stemmed kinds, including the 

 Sargassum which gives name to a Sea, more plenty towards the 

 south. These Brown Algae are the only marine kinds which are 

 exposed with regularity to the air, either between tides on the 

 beaches or during flotation on the surface; and this better access 

 to gas-supply helps to explain their larger and stouter forms. 



Of the RED ALGAE, the best known are the dark-red, almost 

 purple Irish Moss and Dulse, famihar to all persons who have had 

 the good fortune to grow up in a sea-port; the Corallines, those 

 reddish-chalky-warty incrustations upon stones near low-tide 

 mark, often mistaken for corals which they aid materially in the 

 building of coral reefs, though also extending far north of the 

 range of those much misunderstood animals; and the beautiful 

 rose-red, soft-foliaged Sea-mosses, most plenty towards the south, 

 where they often arouse the collecting instinct in persons who 

 never have been moved to collect anything else. 



Such are some of the principal ones of the fourteen thousand or 

 more different kinds of Algae which botanists have named and 

 described. 



