CHAPTER V 



THE ORGANIZATION OF THE PLANT 



The great plant groups. The vegetation of the earth con- 

 sists of a bewildering variety of forms. At one extreme 

 are plants consist- 

 ing of a single cell 

 and therefore lack- 

 ing roots, stems, 

 leaves, flowers, or 

 fruits ; at the other 

 are the great trees, 

 like the giant red- 

 woods and euca- 

 lypti, which tower 

 to the height of 

 hundreds of feet 

 and spread millions 

 of leaves to the sun- 

 shine. Some spe- 

 cies are adapted to 

 live in ponds and 

 streams, and spend 

 their whole life im- 

 mersed in water ; 

 others inhabit des- 

 erts in which rain 

 rarely falls and 

 moisture is at the 

 minimum. Between these extremes all sorts of vegetable forms 

 occur. Herbs, shrubs, vines, and trees vie with one another for 



55 



FIG. 28. Pteridgphytes. A colony of walking 

 ferns (Camptosorus) 



