CHAPTER V 



THE FEMALE GAMETOPHYTE 



THE literature relating to the female gametophyte of Angio 

 sperms is so extensive that one can not hope to compass all of 

 its details. We have selected for critical examination numerous 

 examples, well distributed throughout the great groups, and the 

 conclusions from these must fairly represent the present state 

 of knowledge. Even in these cases it would be hopeless to 

 attempt the presentation of all the details to which attention 

 has been called, and only those will be considered that seem 

 most significant. There is a prevalent impression that with 

 very few exceptions the history of the female gametophyte is 

 rigidly uniform, but an examination of the literature reveals 

 considerable variation. This impression has doubtless arisen 

 from the fact that the standard texts have almost uniformly 

 selected a single type of history for description. 



The important literature of the subject dates from Hof- 

 meister, 1 ' 2 whose work was supplemented and corrected by 

 Wanning, 3 Vesque, 4 Strasburger, 5 Fischer, 6 Marshall-Ward, 8 

 Treub and Mellink, 10 Guignard, 11 ' 12 and others. During the 

 last twenty years numerous investigators have added to the lit- 

 erature, and much of their work will be referred to later. 



It was stated in the previous chapter that we regard the 

 history of the female gametophyte as beginning with the divi- 

 sion of the mother-cell. The ordinary product of this division 

 is an axial row of cells whose morphological nature was long 

 a subject of discussion (Figs. 28, 29). By many they were 

 regarded as mother-cells that do not divide, bui at present there 

 is general agreement with the view, stated by Overton 28 (p. 

 172) in 1893, that they are megaspores. This means that the 

 usual row of four cells produced by the mother-cell represents 

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