V. 
Recent Observations on Fertilisation and 
Hybridity in Plants. 
HE object of the following paper is to bring before the readers of 
NATURAL SCIENCE the most recent results which have been 
attained by workers in that department of Plant Physiology which 
relates to the actual process of the fertilisation of the female by 
the male element, and of the secondary processes by which the access of 
the active to the passive element is assisted. The enquiry naturally 
divides itself into two branches: (1) The nature of the process itself ; 
(2) The subsidiary phenomena. The first of these enquiries evidently 
goes to the foundation of the laws on which depends the succession of 
life on the earth. Observations on this head, to have any value, 
must be carried out by experts of great knowledge, and with trained 
skill in the use of the most delicate microscopical appliances; the 
lowest forms of life, as well as the highest, must be put under requi- 
sition to yield up their secrets. As we ascend in the scale of 
organised beings, the various vital processes become more compli- 
cated, and secondary phenomena play a larger parc in them; and it 
is in Flowering Plants that these become most interesting and most 
within the scope of the non-scientific observer. As, therefore, this 
will be the most familiar branch of the subject to those of our readers 
who have not made the physiology of plants their special study, we 
propose to commence with it. 
The process by which the ovule of Flowering Plants is fertilised 
by the pollen-grain—7.c., is acted on so as to be enabled to produce an 
embryo, without which no seed can germinate—is sufficiently 
well-known. The pollen-grain (the male element) must first 
be deposited on the stigma, where it puts out a_ pollen- 
tube which penetrates into the embryo-sac of the ovule, and 
there, coming into contact with one of the embryonic vesicles (the 
female element) fertilises it, the result being the growth of the 
embryo within the embryo-sac. The subsidiary phenomena are here 
the conveyance of the pollen-grain to the stigma, and the entrance of 
the pollen-tube into the embryo-sac. In the last-named process a 
great uniformity prevails throughout the Angiosperms or larger 
section of Flowering Plants; the only important exception being the 
