ON REPRODUCTION. 371 



PART III. 



1. ON THE REPRODUCTION OF FERNS. 



In Phsenogamous plants, the flower and its parts, con- 

 sisting of calyx, corolla, stamens, pistils, ovary, seed, posi- 

 tion and mode of germination of the embryo fdrnish 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- 

 nate, presenting very beautiful microscopic objects. Much 

 examination is, however, yet required before they can be 

 made practically available for assisting in defining genera or 



