LUTHER BURBANK 



That vast tribes of plants should have found it 

 necessary to adopt both methods of propagation 

 is in itself an evidence of the struggle for existence 

 that is the basis of natural selection. 



In another way, also, the bulb perhaps evi- 

 dences the hardness of the struggle for existence, 

 particularly in tropical climates. Everyone knows 

 that vegetation is exceedingly luxuriant in the 

 tropics, and it is a matter of observation that the 

 habit of developing tubers and bulbs is especially 

 common among the herbaceous plants of tropical 

 and sub-tropical regions. Perhaps one explana- 

 tion is that the storing of food-supplies in the bulb 

 enables the young plants to shoot up rapidly 

 without waiting for the development of a large 

 root system. 



By so doing they may stand a chance of com- 

 peting with the surrounding vegetation and thus 

 have a far better chance of reaching maturity than 

 if they had grown from tiny seeds. 



It is probable, therefore, that the generality of 

 bulbous plants that one would find in any given 

 locality in their native haunts would have devel- 

 oped as offshoots of the bulb of an original plant 

 or as inbred or close-bred. So the bulb has very 

 fundamental importance in the plant economy. 

 And it is interesting to reflect that it is correspond- 

 ingly important from a human standpoint, inas- 



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