28 



or dorsal suture of the two carpels is very easily and surely estab- 

 lished at D, D. In the normal fruit a smooth or uncrested dorsal 

 suture must be sought beyond a placenta to either side of this. 

 In the normal fruit the uncrested dorsal suture is represented by 

 a smooth furrow, the only smooth furrow on the fruit, the posi- 

 tion of the placentae being indicated externally by a groove of 

 about the same rough nature as the remainder of the surface. In 

 the monstrous fruits smooth furrows are found at d, d, and since 

 these are the only positions which fulfil the condition mentioned 

 above for the uncrested outer or dorsal suture, their nature 

 seems clear. In the fruit, then, two placentae, a and B, repre- 

 sent the edge of carpels of a single fruit, while the other two, e 

 and /, represent the edges of carpels from the two fruits ; in the 

 same way, the upper and the lower of the four horns are each 

 composed of parts from the two joining fruits, while the two lat- 

 eral horns each represent the edges of the two carpels of a single 

 fruit. It is evident that if this assumption be true, some of the 

 parts of the fruit have a quite different proportional development 

 from what they do in the normal fruit, but this is not at all sur- 

 prising. 



While, as stated above, the evidence of young material is very 

 desirable, the explanation here given is the only one I am able 

 to suggest which will explain the observed sutures as a case of 

 syncarpy in which the coalescence of the carpellary elements of 

 the two fruits has taken place along the edges which form the 

 ventral sutures in the normal fruit. 



The flowers are usually borne in a raceme, but it occasionally 

 happens that one is produced from the main stem a little below 

 the base of the raceme. Such a case is illustrated in the figure. 



The figure represents a lateral view of one of the syncarpous 

 fruits, both of which were approximately identical in form, cross- 

 sections of normal and abnormal fruits, and the anomalous in- 

 sertion of a fruit on the main stem below the pedicel. 



Missouri Botanical Garden. 



