444 Dr. L. Radlkofer on Fecundation in the Vegetable Kingdom, 



loping membrane. That we are still in some uncertainty on 

 this point, appears scarcely more than a gap in our knowledge ; 

 the recognition of the phsenomena known to us as a process of 

 fecundation perfect hj corresponding to that of animals , can no 

 longer be delayed by this. 



The fecundating corpuscles of the plants as yet referred to, 

 possess a peculiar, as we usually say, independent motion, like 

 the spermatozoa of most animals. Of most ? Even in animals 

 this is not a universal property of the fecundating corpuscles. 

 It is absent in the Isopoda and Amphipoda. Its absence will 

 not therefore deter us, in plants, from acknowledging as fecund- 

 ating corpuscles, things, which on other important grounds we 

 are obliged to accept as such. We find ourselves in this position 

 in reference to the corpuscles contained in the antheridial cells 

 of the Floridese. Yet at present we can scarcely venture more 

 than conjectures as to the fecundating process of these plants ; 

 we are still in uncertainty which of the parts capable of being 

 regarded as ova, really have that import. 



In the Charge^ also, in which we are acquainted with motile 

 spermatozoids, it remains for future researches to furnish evi- 

 dence of the conjecture ventured on in an earlier page, that the 

 young (primordial ?) spore-cell has the import of an ovum. 



Neither the independent movement, therefore, of the sperma- 

 tozoids, nor, as we have already noticed above, their independent 

 form, appear to be essential properties in reference to their final 

 destination — the fecundation of the ovum. They appear only 

 essential to this in ensuring that the fecundating substance, the 

 substance of which the spermatozoids is composed, arrives at the 

 place of its destination^. Consequently we have no need to be 

 surprised if Nature, where (to speak anthropomorphically) she 

 can accomplish this object in a different way, does not in the 

 first instance organize the fecundating substance into the form 

 of spermatozoids. We meet with this case in the Phanerogamia. 



By my researches I have established with scientific cer- 

 tainty, that the embryo of the Phanerogamia is produced, not 

 from the end of the pollen-tube, but from a cell — the germinal 

 vesicle — existing in the embryo-sac before the pollen-tube arrives 

 at the latter. Further, it is the general rule, that this remains 

 undeveloped when it does not receive the influence of the pollen- 

 tubef. The fact that no one has happened to think that the 



* We are at present ignorant of the arrangement by which this is effected 

 iu the animals with motionless spermatozoa. 



t In recent years little faith was any longer placed (Mohl, ' Vegetable 

 Cell,' 1851) in the assertions frequently made by the older authors, of ex- 

 ceptions to this rule, in Cannabis saliva^ Spinacia, and Mercurialis {vide 

 Bernhardi, Sur la Formation des Graines sans I'aide de Fecondation. Ann. 



