CHAPTER XVI. 



THE CARPEL AND OVULE. 



The Gynoecium, or Pistil, occupies the centre of the Flower. Its office 

 is to produce ovules, and after their fertilisation to nourish and protect 

 them, together with the new germ that each may contain. This 

 nursing function is continued till the time of ripeness, when the Seeds 

 are shed. The Gynoecium is thus the most persistent part of the 

 Flower. While the sepals, petals, and stamens are liable to fall away 

 after the period of blooming, the gynoecium remains attached until 

 the seed is ripe, continuing to draw from the receptacle the nourish- 

 ment required for the germ. The term Fruit is applied to the whole 

 Pistil when fully matured. 



The Gynoecium is composed of Carpels, which may vary in number 

 in different cases from many downwards to one. Associated with 

 them are the Ovules, or Mega-Sporangia, which also vary from large 

 numbers in some cases down to one in others. Two parts of the 

 gynoecium may be distinguished by their structure and function. A 

 distal region, which offers at the time of blooming a receptive surface 

 for the pollen-grains : this is called the stigma ; and a basal part, 

 distended as the ovary, which encloses the ovule or ovules. Frequently, 

 and especially in syncarpous pistils, an elongated region intervenes 

 which is called the style (Fig. 209). 



The Carpels are leaves. Often that can easily be recognised, as 



in the Pea, where the pod represents a single carpel ; or in Caltha, 



where there are many (Fig. 208). In this case they are all separate 



from one another (apocarpous), and their foliar nature is undisguised. 



Each leaf is folded so as to envelop the ovules borne on its margins, 



the midrib is turned outwards from the centre of the flower 



(Fig. 210). The foliar nature of the carpels is less easily recognised 



where they are united (syncarpous), as they are in the Lily. But even 



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