THE FLOWER AND FRUIT 



93 



stamens; and, as Coulter and Chamberlain (i) point out, this may 

 be interpreted "as a case in which the primordia of stamen and 

 petal have a common origin, entirely analogous to the sympetalous 

 corolla with stamens 'inserted on its tube,* but in which the 



Fig. 34. A-H, stages in the development of the flower of the apple showing epigyny. 

 The stippled regions indicate the pith of the axis. /, a young flower bud showing epigynous 

 character and vascular system. /, diagrammatic representation of the vascular system of 

 the apple. (Redrawn and adapted from Kraus.) 



separate primordia of the petals have been delayed in their appear- 

 ance." 



The character of the symmetry of a flower also constitutes a 

 point of variation. In the actinomorphic forms, the parts of the 

 flower are arranged in a radial symmetry; while, in the zygomorphic 

 type, the flower is bilaterally symmetrical and can be divided in 

 only one plane of symmetry. The former occurs in the majority of 

 cases, while the latter more specialized type is represented in many 

 legumes, including Pisum and Medicago. 



In contrast with the view that the vegetative and floral axes 

 are fundamentally alike, and that the foliar and floral organs are 

 similar in the initial stages of their development, Gregoire (7) 



