298 THE LIFE OF THE PLANT 



another ; otherwise, what other meaning can we attri- 

 bute to these rudimentary or rather degenerate organs 

 which meet us at every step, and demonstrate a gradual 

 transition between dissimilar forms ? 



The study of organisms in the embryonic stage 

 proves this theory still more conclusively. All the 

 data of embryology testify that similarities and homo- 

 logies, which escape attention in fully developed 

 organisms, become comprehensible when the history 

 of their development is studied. Thus, for instance, 

 there is no wider or more fundamental difference in 

 the vegetable kingdom than that between spore-plants 

 and seed-plants ; an impassable abyss seems to lie 

 between these two sub-kingdoms, and yet Hofmeister 

 managed to bridge even this gulf. The study of the 

 history of the development of the higher spore-plants 

 and of the lowest seed-plants has revealed the exist- 

 ence of a connexion between these groups, and has 

 even shown the course which this transition must have 

 taken. We have already seen that the most typical 

 spore-plants, such as ferns, are fertilised by means of 

 antherozoids, whereas seed-plants are fertilised by 

 means of pollen-tubes. Hofmeister predicted, on the 

 ground of his far-reaching investigations, that inside 

 the pollen-tubes of certain flowering plants anthero- 

 zoids would necessarily be discovered, and twenty years 

 after his death this prediction was actually fulfilled. 

 The exact sciences, such as astronomy, physics, and 

 chemistry, pride themselves upon such predictions. 

 Hofmeister's prediction is the most brilliant in the 

 domain of morphology.^ The Gymnosperms, to which 

 our Conifers belong, form a link between the two sub- 

 kingdoms of the vegetable world. It is in some members 

 of this group that antherozoids have been discovered. 



1 It is very strange that Prof. Borodine has found it possible not even 

 to mention the name of the great scientist in his detailed work upon this 

 subject [The Process of Fertilisation in the Vegetable Kingdom). 



