1 88 Education through Nature 



This plant belongs to a group of simple plants 

 called Algae. There are numerous kinds of algi living 

 both in salt water and in fresh water. The salt-water 

 forms are often very beautiful and are called sea- 

 weeds. They have various colors, but blue, brown, 

 and red are the prevailing forms, and hence algi are 

 classed as brown, blue, red, and green algi. The 

 coloring-matter enables them to live like ordinary 

 green plants, manufacturing their own food from 

 the inorganic elements of the water by the aid of 

 sunlight. 



The algi are related to another group of simple 

 plants called fungi. These are such plants as molds, 

 seen on bread, preserved fruits, leather, horn, and 

 other decaying organic substances, and plants like 

 the toadstools, mushrooms, and puffballs, often found 

 growing on decaying bark or springing from com- 

 post heaps. Mildews, rusts, and smuts, also growing 

 on leaves of plants or the ripening fruit of grains 

 and grasses, belong to the fungi. 



FUNGI. These fungi differ from the algi chiefly 

 in being devoid of chlorophyl or coloring-matter. 

 They are consequently unable to live like ordinary 

 plants, and must obtain their food already prepared 

 as organic substances from other plants or animals, 

 and are consequently called parasites or saprophytes, 

 according as they attack living or dead forms of plants 

 or animals. Some of these are useful to man as food; 

 but the majority of them are harmful, inasmuch as 

 they often injure the organisms on which they live. 

 Rusts and smuts are parasites that are injurious to 

 cultivated plants such as wheat, oats, and corn. 



Both the algi and the fungi contain many micro- 

 scopic forms that can be studied only by means of 

 the compound microscope. Many of them, however, 

 are easily found, and can be readily studied by the 

 aid of a hand-lens or even with the unaided eye. The 



