THE GROWTH OF A SEED 27 



ing again. We have bred the cultivated potato into the habit f storing larger 

 quantities of starch in its under ground tubers, and this, too, has been brought 

 about by a gradual accumulative selection of those that develop this habit 

 to the greatest extent. Left to themselves, there is a constant tendency to 

 revert into original and inferior forms. 



Our tomatoes are the result of long selection, starting with a cross of the 

 smooth and hollow forms on the crooked and solid fleshed sorts, we have by 

 accumulative selection gotten the knobby tomato inside the smooth skin of 

 the hollow one, and we find yet that it is hard to keep it there, and the volun- 

 teer plants that annually come up in the garden are apt to revert into one 

 or the other of the original forms. 



