258 Field, Forest, and Wayside Flowers 



female. In a few fern-allies the prothallus male 

 or female as the case may be is minute and color- 

 less, and remains throughout its brief life partially 

 enclosed within the spore from which it grew. 

 From such plants as this there is but a short 

 upward step to the cone-bearing trees. 



But all our familiar ferns of wood, rock, and 

 roadside, the "Filices" of the working botanist 

 become parents of prothalli which escape from the 

 spore in their earliest youth, and live thereafter as 

 independent plants, growing on the surface of the 

 earth, and getting their own honest living by aid 

 of a working-outfit of chlorophyll and root-hairs. 



So there is in ferns a true alternation of genera- 

 tions. The fern gives birth to a prothallus, and 

 the prothallus gives birth to a fern. In this curious 

 genealogy there is no resemblance between parent 

 and offspring, but the offspring is a young copy of 

 its grandparent. 



The fern prothallus corresponds to a small frac- 

 tion of the blossom in a flowering-plant. To prove 

 this it would be necessary to plunge so deeply into 

 structural botany that the reader might find the 

 comparison, like many another, odious. 



The life-story of the prothallus resembles that of 

 the flower in these respects, that it lives to accom- 



