SYMMETRICAL FLOWERS 



3d 



^-AX 



W 



/ / / 



in the androecium of the mustard, where the multipHcation of two of 

 the stamens, each into two, has occurred. The development in a united 

 condition of two or more organs originally 

 separate is called Syngenesis. This is exhibited 

 in the two carpels of the mustard, which are 

 united to form a single pistil. 



The nature of the process is illustrated by 

 the accompanying diagram (Fig. 30 A). Let 

 a represent a mass of elementary tissue which 

 is normally to develop into a stamen. If it 

 develop by a uniform growth throughout the 

 mass, it will become a single stamen, d. If, 

 upon the other hand, it grow separately at the points h, c, and d, it 

 must result in the production of three separate bodies, each of which 



^^ 



Fig. 30 A. Diagram illustrating 



the process of chorisis. 



Figs. 31 and 32. Tetramerous flower of olive, 6 of its stamens and 2 of its carpels suppressed. 31. 

 Same in longitudinal section. 33. Androecium of mustard, showing a stamen developed as two, 

 through chorisis. 34. Flower of Tilia, showing each stamen developed into a cluster and a petal 

 through chorisis. 37 shows such a cluster detached. 35. Diagram of transverse section of Magnolia, 

 showing duplication through metamorphosis. 3G. Flower of strawberry, the calyx-appendages simu- 

 lating an cpicalyx. 38. Androecium of Fsorospermum, the stamens of one set undergoing chorisis, 

 those of the other aborted into gland-like bodies. 39. Flower of Stellaria, the corolla apparently 

 double. 40. A petal of the same, bi6d by chorisis. 41. Flower of rarojacHW, the calyx having under- 

 gone chorisis. 



may become a perfect stamen, as represented by the dotted lines. The 

 process thus results in branching. 



