10 
THE TEEN WORLD 
minute, active, thread-like bodies called spermatozoids. At a 
certain stage in the germination of the spore, the frond-bud 
emerges from its cell, and the spermatozoids about the same 
time issue forth from their cells, and coming into contact with 
the bud or embryo, the latter becomes fertilized. Soon after 
this process has been completed, the spermatozoids lose then- 
activity and finally disappear. The prothallus, too, commences 
to decay, and finally, with its little system of cells, it dies, 
leaving in its place only the fertilized frond-bud, which, how- 
ever, at this stage has no defined likeness to the future and 
complete frond. The under portion of the frond-bud lying- 
next the damp soil soon however begins to form the root- 
stock, which subsequently gives rise to the rootlets that 
absorb and convey to the plant the moisture without which 
it could not live, whilst from its upper portion proceeds 
the stalk. 
Steadily the process of development continues, until at 
length a tiny Fern is produced, whose form and habit begin to 
assume a likeness to the form and habit of the parent plant. 
In all Ferns which are not annual, including the large 
majority of this class of plants, the process of development is 
so slow that it is generally two or three years before it is 
completed. This is the case with the small ami herbaceous 
species, whilst in the case of the shrub-like and the tree Ferns, 
the period from the commencement to the completion of 
growth is considerably longer. 
Not the least wonderful circumstance in connexion with 
the minute germs of Fern life is their singular vitality. The 
dust-like spores, if kept secure and dry for a long period of 
years, will often, even after such an interval, when subjected 
to the necessary degree of heat and moisture, commence and 
continue the process of development. 
