PLANTS CARRY LIFE INSURANCE 135 



mon vegetables, such as Irish potatoes. These po- 

 tatoes, if cut into pieces, without having their "eyes" 

 damaged, and placed in the right kind of soil and 

 climate, will soon develop into new potato plants. 

 Not many bulbous plants have "eyes": that is, the 

 places from which the new plants spring, as in the 

 potato; but those that do not usually develop sep- 

 arate bulbils. That part of the potato other than 

 the eyes is the food insurance that the parent potato 

 has stored up to feed the new plants until they are 

 able to get nourishment from the soil. 



Some plants protect their food insurance by 

 burying their stems underground; the stems thus 

 buried are known as rhizomes. Solomon's seal, 

 sedges, iris all these bury their stems under the 

 soil; but other plants, many of which grow in the 

 tropics, like tree-ferns, owing to the mild climate do 

 not need to conceal themselves from the inclement 

 weather by burrowing underground. 



In bulbs and rootstalks which are protected un- 

 derground, not only a sufficient quantity of food- 

 material is saved to feed the plant, but often enough 

 is contained to form new bulbils. Especially is 

 this true of lilies, tulips, dahlias, crocuses, and hya- 

 cinths. 



The century-plant of the western plains stores 

 up food for a number of years, preparatory to bios- 



