ON REPRODUCTION. 871 
PART III. 
l. ON THE REPRODUCTION OF FERNS, 
In Phenogamous plants, the flower and its parts, con- 
sisting of calyx, corolla, stamens, pistils, ovary, seed, posi- 
tion and mode of germination of the embryo furnish the 
data on which all systematic arrangements are based. 
With the exception of the embryo these organs are in 
general visible to the naked eye, and require but little aid 
from the miscroscope, This, however, is not the case with 
' Ferns, at least as regards their organs of reproduction, 
for although they have no visible stamens and pistils like 
_ flowering plants, for generating seeds, nevertheless it was 
= known to early observers that they had seeds, but so 
small as to be invisible to the naked eye; the microscope, 
however, revealed that they are of definite forms, which 
was first observed by W. Cole in 1669, and it is recorded 
that young Fern plants were raised from these invisible 
seeds in the Oxford Garden in 1715. 
At page 8 it is explained that these seeds are called 
Spores, and are contained in cases called sporangia, 
which are of various forms, the form most common being 
girded by a ring. When the sporangium is mature, the 
. elasticity of the ring causes it to burst, and, under favour- 
. able circumstances as regards light, the spores are seen 
.. to issue like a puff of smoke; this apparent smoke consists 
. Of atoms varying in form in the different genera, being 
globose, oval, or angular, smooth, plain, striated, or echi- 
3 | nae, presenting very beautiful microscopic objects. Much | 
. examination is, however, yet required before they can be 
made practically available for assisting ia defining genera or — 
