THE ABORTION OF OVULES 361 



of contiguous seeds that have failed. These seeds when they 

 aborted in the living fruit could not have been more than a 

 sixth of the normal length, and when the failure took place the 

 pod was probably about a third of its length when mature. 



The above results of my examination of the pods of Erythrina 

 cor alio dendron would lead one to infer that the narrowest con- 

 strictions, where not a trace of ovule or seed is to be recognised, 

 are concerned with a much earlier stage of abortion, and this is 

 also indicated by the terminal pointed beak. One may suppose 

 that there were rudiments of ovules in the flower that were 

 unable to respond to the fertilisation of the ovary, thus restrain- 

 ing the response of the ovary in those places to the stimulus 

 of fertilisation. In this connection we have to bear in mind 

 that the fruit as well as the seed is a product of pollination. 



The flower in the case of the seven-seeded pod above 

 described probably displayed thirteen ovules in its ovary, 

 which I imagine would be typical for the species. Doubtless 

 there were the rudiments of six or seven other ovules in the 

 ovary, taking the beak of the fruit into consideration ; and the 

 primal complement of ovules was therefore probably twenty, 

 though the other seven ovules need never have passed beyond 

 the primordial stage. In other words, to adopt Dr Goebel's 

 standpoint with regard to rudimentary organs in plants, the 

 assumption of a primal complement of ovules larger than that 

 of existing flowers does not require us to assume that all of 

 them " functioned " as mature ovules. Such were some of the 

 speculations that passed through my mind when I examined 

 the first moniliform pods ; and they have been exceedingly 

 helpful to me ever since. 



The moniliform pods of Sophora tomentosa were examined Sophora 

 in the moist condition. A typical legume contains six or seven °'"^" °^*' 

 seeds separated from each other by narrow necks which often 

 enclose shrivelled aborted seeds i to 3 millimetres long, the 

 length of the neck depending on the number of aborted seeds, 

 as indicated in the accompanying figure. We seem to be only 

 concerned here with the failure of young seeds ; but still earlier 



