452 Scientific Proceedings, Royal Dublin Society. 



sperm" comparable with a spermatozoid, and the female cell is not 

 always an " oosphere.' 



If, then, we accept the terms "androgamete" and " gyno- 

 gamete," the union of the two can be defined as " zygosis," and the 

 product a "zygote" or "ovum," both these latter terms being al- 

 ready accepted by botanists. We can thus indicate the essential 

 part of the sexual process — the union of the male and female ele- 

 ments, protoplasm with protoplasm, and nucleus with nucleus — as 

 zygosis ; and we can easily distinguish any preliminary steps in 

 the whole process of fertilisation ; as, for example, in the higher 

 flowering plants, where pollination, or application of the pollen, 

 precedes the process of zygosis, if the actual fusion of the repro- 

 ductive elements can be held to occur in all cases. It is important 

 to note that the term " ovum" must be regarded as the exact equi- 

 valent of zygote, the ovum being the new cell formed by the union 

 or conjugation of one or more androgametes and the gynogamete. 



Passing one step further, we may now indicate the cases in 

 which the male and female sexual elements are formed as the 

 gametangia, a term already used and adopted, and we can at once 

 distinguish between the androgametangia and the gynogametangia. 

 The structure of these two organs varies very much, and we have 

 the antheridium as the typical androgametangium, and the arche- 

 gonium as the typical gynogametangium. Sachs {Vorlesungen, 

 p. 887) proposes to use the terms " spermogonia " for the male 

 organs, and " oogonia " for the female ; but both these terms are 

 quite inadmissible, the word spermogonium having been applied to 

 special structures in the Fungi and Lichens, which are now known 

 to be non-sexual, and the word oogonium is in common use, and is 

 merely a rudimentary archegonium. 



If we now take the plant that bears the gametangia, it is easy 

 to denominate it the gametophore (a term I have now used for some 

 time) ; and in such instances as in the prothalli of Equisetum, where 

 the male and female organs are produced on different plants, the 

 two plants can be called the androgametopliore and the gynogameto- 

 pJiore, respectively. 



As we can thus obtain a perfectly consistent set of terms, with- 

 out really adding to the burden of botanical terminology, I would 

 strongly urge the rejection of Mr. Dyer's term " oophore," as it 

 is only applicable to the plant bearing the fertilised ovum. 



