258 PEINCIPLES OF PLANT-TEEATOLOGY. 



In other instances the reason of the suppression is 

 quite obvious, and lies in the diversion of the necessary- 

 nutriment in order to form new and extra structure* 

 which do not occur in the normal flower, as in the 

 Mimulus just mentioned. A similar example was seen 

 in a double flower of the common stock {Matthiola} 

 which had proliferated above the insertion of the 

 corolla into an inflorescence, both stamens and pistil 

 being on that account entirely suppressed. 



Normal examples of unisexuality are very numerous, 

 and have been derived from the bisexual condition. 



4. Carpels. — Syncarpy. — As the syncarpous- 

 character of the pistil is by far the most frequent 

 under normal circumstances, great frequency of this- 

 feature as an abnormal occurrence is precluded. 



The few cases known are special ones. In Amyg- 

 dalus and Primus there is occasionally to be found an 

 increase in the number from the normal single one- 

 to from two to five carpels ; this is accompanied by 

 fusion of the carpels to form a syncarpous ovary like- 

 that of the Pomese. 



When, in the scarlet runner {Phaseolus multiflorus} 

 or kidney bean (P. vulgaris), two to three carpels in 

 place of the normal single one appear, these are often 

 either partially or completely united to form a syn- 

 carpous pistil. The same thing has been observed in 

 the garden pea {Pisum sativum) and Gleditschia. 



In the Sfei Valery apple the ten stamens, during 

 their transformation into carpels, become united to 

 form a syncarpous ovary perfectly resembling the 

 normal one in the tier below. 



Fermond mentions that in Delphinium elatum 

 several carpels were coherent, whereas normally the 

 pistil consists of discrete follicles. The same thing 

 has been noticed in Helleborus. Now this union of the 

 carpels, be it observed, is the normal feature in love- 

 in-a-mist (Nigella). 



Some instances of reduction in the pistil are due to 

 intimate fusion of two or more carpels. A very 



