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- 
