


СНАРТЕК У 
FERN CROSSING AND HYBRIDIZING 
THE possibility of crosses being effected between different species 
or different varieties of Ferns was long doubted by botanists, even 
after the final steps completing the knowledge of the life cycle of 
Ferns were taken by Naegeli and Suminski, which demonstrated 
that the reproduction of a Fern through its spores resulted, as 
with flowering plants, from the coalition of two sexual elements, 
formed separately and brought together in the act of fertilization, 
these eventually producing an embryo seed by their conjoined 
influence. The difficulty of the scientist in accepting the cross 
fertilization of Ferns as a demonstrated fact arose from the circum- 
stance that owing to the microscopic nature of the organs concerned, 
and still more of the operation involved, it was impossible to make 
experiments on the same easy lines as is practicable with flowering 
plants, whose pollen could be transferred from one flower to another 
by hand, and precautions taken to prevent fertilization from 
alien sources, or self-fertilization, so that eventually if seed be 
formed and plants result of mixed character, it is scientifically safe 
to say that such plants are crossbred and are not merely independent 
“sports.” Hence when Ferns were found or raised displaying 
mixed characters, there was no absolute evidence available regard- 
ing their mixed origin, and it could only be assumed from the joint 
features displayed. It was due to Mr. E. J. Lowe to produce con- 
vincing evidence, which the botanist was compelled to accept, 
since he intentionally sowed together the spores of Polystichum 
aculeatum densum, a distinctly congested variety of that species, 
with those of P. angulare Wakeleyanum, a variety in which the 
ріппге were set on in pairs at obtuse angles to each other, so that 
with the opposite pairs so characterized, a cross was formed, a 
rare feature and entirely unknown in P. aculeatum. The result 
was several plants in which distinctly aculeatum characters were 
associated with the cruciate or cross-forming pinne of P. angulare. 
A close study of the mode in which fertilization occurs shows that 
although, under ordinary circumstances, self-fertilization must be 
the rule, cross-fertilization was by no means an impossibility, and 
might even be facilitated by artificial means, if not to the actual 
extent of conveying the one element by hand to the other. The 
spore, under congenial circumstances, forms, as we have seen in our 
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