10 THE FERNS OF SOUTH AFRICA 
Some with short rhizomes produce several side buds if the 
terminal bud be removed, and with some others buds are 
produced on the very base of the frond stalk, after the frond 
itself has been withered down for years. 
The only South African kind in which buds are produced 
on the roots is Hypolepis Bergiana , which is so common where 
it occurs that it is seldom examined, and consequently this is 
often overlooked. 
It is necessary to revert again to the spore, in order to 
make more clear the life-history of the fern. The spore itself 
has already been referred to as the natural reproductive organ 
of the fern, and as such it takes the place of the seed in 
higher Orders of plants. But the spore is not the direct 
result of sexual fertilisation, as the seed is, and still sexual 
fertilisation dqes actually occur on the prothallus. This brings 
us to the fact that there are two distinct vegetative forms of 
plant, alternating in the same individual. Beginning with the 
spore there is produced from it the small green vegetative 
prothallus ( Gametophyte ), which bearing the sexual organs must 
be considered the more perfect plant. Then comes fertilisa- 
tion, and instead of a seed we get the more complex vegetative 
plant of another form, which in common language is spoken of 
as the “fern” ( Sporophyte ), and this, without further fertilisation, 
produces, in every species, its asexual reproductive spores. 
This alternation of generations, which occurs in varying forms 
and degrees in most cryptogamic plants, and also in some 
forms of animal life, is much more difficult to trace in the 
higher Orders known as Flowering plants or Phanerogams, 
though there also it is claimed to exist in much modified 
form. But the evident alternation of generations, which has 
been described as part of the life-history of ferns proper, is 
considerably modified even in the case of some of the plants 
known as Fern Allies, and is one evidence of how, in long-past 
ages, evolution worked its miracles, and gradually produced 
our now highly diversified flora from one common stock, some 
of the developing links which have meantime become extinct 
being known only as fossil remains, while others doubtless 
remain unknown. 
