NUCLEAR PHENOMENA OF SEXUAL REPRO- 

 DUCTION IN ANGIOSPERMS 1 



PROFESSOR D. M. MOTTIER 



What constitutes sexual reproduction, fertilization or 

 fecundation is so variously set forth in botanical litera- 

 ture that one naturally approaches a discussion of this 

 subject with some timidity. Having been assigned the 

 group angiosperins, in which a definition of sexual phe- 

 nomena may be made more specific by concrete illustra- 

 tion, it seemed at the outset that a part of my task, at 

 least, was simpler than that of some of my colleagues 

 who take part in this section of our program; but a 

 moment's thought convinced me that what might be 

 gained from this limitation of my field was probably 

 much less than the opportunities offered by the scope 

 and diversity of phenomena in groups of lower plants. 



In the preparation of this paper, the writer has kept 

 clearly in mind the fact that the phenomena of sexual 

 reproduction implies explicitly that a special significance 

 is attached to the nucleus as in a large measure distinct 

 from any function, or role of the cytoplasm; consequently 

 he will deal first chiefly with nuclear behavior, leaving 

 a discussion of the relation of nucleus and cytoplasm to 

 be dealt with in a later paragraph. 



Sexual reproduction in phanerogams implies the union 

 of especially developed cells known as gametes, and the 

 development of an individual plant from such union. 

 While in this process the union of the nuclei is held to 

 be more important, it is not inferred that the part taken 

 by the cytoplasm is unimportant, but the writer does 

 insist that the cytoplasm plays a secondary role in the 



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