164 ■ :©otanB 



grow in hot si)rings, where the water is so warm you 

 can scarcely bear your hand in it; some of them, the 

 tiniest of all, the red-snows of the arctic regions, 

 grow u2:>on snow fields. 



The sea-weeds offer us most pleasing studies. The 

 broad leaf -like, sometimes much-branched part is 

 called the frond, also the thallus. This may have a 

 stalk and a root-like expansion ; these do not serve 

 any ordinary purpose of stem or root, they merely 

 fasten the weed upon some stone or shell, and permit 

 it to wave gently about in the water. In this waving 

 motion the algse are fishing, as the barnacles do, 

 gathering food from the water and the air in the 

 w^ater ; for, like all other plants, their food is mineral 

 substances held in solution, and gases gathered from 

 the air, such as carbon dioxide and oxygen. 



Some sea-w^eeds are merely straight, coarse grass- 

 like blades, as the abundant California weed ; others 

 are coarse, of a dull olive green, much branched, like 

 the bladder-wrack which often lines the shores. 

 Others are broad, curly fronds of green, red, brown, 

 or nearly white, as the various kelps. The waters 

 of the ocean are sometimes so full of a moderately 

 coarse red w^eed, like a tangle of crimson strings, that 

 the great waves lose their green color and white, 

 foamy curves, and Ijreak upon the beach like waves 

 of blood. 



