FLOWERING PLANTS INTRODUCTORY 



105 



B 



FIG. 56. Diagrams of arrangements of ovules in the 

 ovary. A, Marsh Marigold ; B, Wild Hyacinth ; 

 C, Violet ; D, Primrose. 



the ovary along the lines of junction of the carpels. The pistil 



of the Violet is an example of this (Fig. 56, c). Another important 



type of attachment of 



the ovules is when, as in x-rr-^ c 



the Primrose, the ovary 



has only one cavity, but 



the ovules are borne on 



a projection from the 



base of this and do not 



spring from the walls 



(Fig. 56, D). These ex- 

 amples do not in any 



way exhaust the variety 



in the construction of 



the ovary, but will serve 



to indicate the import- 

 ance of examining it very 



carefully in studying any 



flower. This is also 



important as enabling the construction of the fruit to be 



understood. 



In the same way, as parts of the same whorl may become united, 



parts of two succeeding whorls 

 may be joined by being lifted 

 up on a common zone of growth. 

 The most common case of this 

 is when the stamens appear to 

 be attached to the inner face of 

 the petals, or to spring from the 

 inside of the tube of the corolla. 

 The diagram (Fig. 57) will make 

 this clear, and examples will be 

 met with below, in the Primrose, 

 the Periwinkle, and many other 

 flowers. 



Another important series of 

 differences in the construction 



pet, petal ; st, stamen ; c, carpel. of flowers depends Upon the 



