CHAPTER XXXVII 

 LOW FORMS OF PLANT LIFE 



252. The earth is covered with life, much of which to 

 the average observer consists of trees, shrubs, weeds, 

 grasses, and cultivated (useful) plants. But these plants 

 which are most visible are not the most numerous. The 

 plants with green leaves are able to take food from the 

 soil and air and to make the three nutrients which are 

 used for growth and which are also stored in the seeds; 

 such plants are considered to be high in the scale of devel- 

 opment or evolution and they serve as food and clothing 

 for man. 



Plants which do not have distinguishable leaves, stem, 

 and roots, we consider low in the scale of development. 

 Many of these low forms of plant life are very useful 

 and necessary for other plants and for man; while many 

 of them are harmful to both higher plants and animals. 

 Some of them are useful in one place and harmful in 

 another; the same can also be said of trees and grasses. 



These low plant forms are divided into two groups, 

 namely, Algae and Fungi. 



253. Algae. Algae have chlorophyll and are able to 

 make starch of water and carbon dioxide, thus preparing 

 their own food. The algae vary in size from the simple 

 microscopic form to the largest plant in the world. The 

 giant kelp of the Pacific Ocean attains a length of over 

 i ? ooo feet; it is an alga. The brown-colored rockweed 



