124 Three Young Crusoes 



The fruit on the back of fern fronds consists of 

 spores instead of seeds; and these spores grow into 

 little heart-shaped prothallia, which produce the true 

 fern plants again. True seeds have little embryo 

 plants tucked away inside of them, and when they 

 are planted these embryos simply have to grow up 

 to be just like their parents. 



