26 THE STORY OF PLANT LIFE 



the apex continuously is indefinite and the branching 

 is racemose. When a terminal bud flowers, and the 

 axis ceases to grow, the, stem is of definite growth 

 and the branching is cymose. 



The buds upon trees are arranged according to 

 certain laws. In some the buds are opposite as in 

 the Ash or Sycamore. In others they are alternate 

 and arranged in two rows on opposite sides of the 

 stem, or in five rows. In the third type the arrange- 

 ment is spiral, as in the Birch and Oak, etc. Their 

 form and arrangement are largely related to their 

 need for protection in winter. 



The buds are young shoots provided with scales, 

 which protect the former in bud, and later fall or 

 persist. The buds may be terminal, or lateral and 

 axillary. The first leaves are scale-leaves in trees 

 and shrubs. Some buds are without scales and are 

 called naked buds. Buds may be leaf buds, flower 

 buds, mixed buds (forming shoot, leaves and flowers) 

 and fruit buds, or the two last. 



The stem may be regarded as a primary axis or 

 shoot with nodes or joints, at which points lateral 

 structures occur (leaves), and the regions between are 

 called internodes. The early shoot is unfolded from 

 a bud. The tip of the bud is the growing point. 



The leaves* serve as organs of nutrition or the 

 media for photosynthesis. They are lateral appen- 

 dages and may be of two kinds, foliage leaves and floral 

 leaves. The perianth is derived from the lateral appen- 



* /, e. foliage leaves. 



