42 Plants and their Ways hi South Africa 



ing plants as you can find, and tell by their positions whether 

 they are branches or leaves or parts of leaves. 



Similarly, by their position we can see that the "leaves" 

 of Asparagus are branches. This will be difficult to understand, 

 especially in the broad " leaved " species, until we see that they 

 grow from the axils of small scale leaves.^ Leaves soon attain 

 their full growth while branches grow on indefinitely. There 

 are exceptions to these statements. The Asparagus branches 

 show an exception to the second statement, as do also the 

 dwarf branches that bear the foliage leaves of the pine, the 

 fruit of apple and peach trees, and others will be found. 



The Law of Correlation of Growth.— This law has 

 been observed by plants for ages. What does it mean ? When 

 a part of a plant is destroyed, the plant's first work is to replace 

 that part. We see how beautifully the law is obeyed when 

 flowers are picked; how many more come to replace them. 

 When leaves are destroyed by locusts or caterpillars, dormant 

 buds which might have remained for ever inactive are given 

 light and air ; the food that would have gone to the destroyed 

 part is turned toward these buds, which grow and unfold new 

 leaves. If shoots are destroyed, new shoots are produced ; 

 while if roots are destroyed, the first thing needed is new roots. 

 Leaves would not unfold if there were no roots to absorb 

 nourishment. When trees are transplanted, some roots are 

 necessarily injured at the tips. The roots are trimmed off, 

 whereupon a vigorous growth of new roots takes their place. 



Fig. 48 shows a young pine seedling which has had its tip 

 cut off. Two buds soon appeared in the axils of the cotyledons. 

 The tip, which was placed in the ground, began to form the 

 lacking roots. This demand upon the plant retarded the 

 growth of the stem, which made no evident growth, while the 

 branches on the seedling increased nearly 3 inches. As 

 a pine tree grows older it loses the power of renewing lost parts. 

 If the tip meets with injury, a side branch will shoot upward 

 rapidly and take its place, leaving only a vacant space to tell 



'Asparagus, with broad green branches (Phylloclades), is often mis- 

 called Smilax, which has green leaves — not scale leaves. 



