DISPERSAL OF SEEDS. 149 



dispersal of seeds the uses of the different 

 kinds of seeds and fruits will be seen. 



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DISPERSAL OF SEEDS. 



1. There are four principal methods by 

 which seeds are distributed:-- (I) Wind, ('2) 

 Water, (3) Animals, the seeds being carried 

 cither inside or outside the animal, (4) By some 

 explosive apparatus. 



2. Wind. Many seeds, for instance those 

 of most orchids, are extremely small and light, 

 so that they readily float in the air Some 

 large seeds are carried about in a similar man- 

 ner, and these are usually provided with 

 thin appendages of various kinds known as 

 'wings.' Good examples of winged seeds are 

 those of the mahogany and 'cedars.' Other 

 wind-borne seeds are provided with downy or 

 silky hairs which enable them to float, for in- 

 stance French cotton, cotton, silk cotton, wild 

 ipecacuanha, lettuce and many grasses. 



3. The seeds of many plants lie at the bot- 

 tom of dry seed -cases (often open only at the 

 top) and out of which it looks extremely 

 difficult, for the seeds to get until the seed- 

 case decays. On a still day this is so, and 

 no seeds escape. When, however,- there is 

 a strong wind blowing, the plahis are shakeii 



