THE INFLORESCENCE AND THE FLOWER 115 



and strong. At its upper end the integuments do not 

 cover it but leave a little aperture, the micropyle. Each 

 ovule contains a single thin-walled spore, which often 

 occupies a very large space in its interior. It is often 

 called the embryo sac, 

 from the fact that the 

 embryo is developed in 

 its interior. 



The ovary is only the 

 basal part of the carpel 

 or the pistil. There is 

 always a sticky apex to 

 it, which is the stigma. 

 The stigma is usually 

 placed at the top of an 

 elongated part of the 

 pistil, seeming to arise 

 from the top of the ovary 

 this is the style. 



The pistil is always the 

 terminal whorl of the 

 flower. Some flowers, 

 however, owing to a 

 curious mode of growth 

 of the axis, which be- 

 comes concave and comes to surround and often to cover 

 in the carpels, appear to bear their stamens and perianth 

 above the ovary. The latter is then termed inferior. 



Many flowers are not provided with all these parts. 

 It is not at all uncommon to find that the corolla is not 

 developed. In such cases it frequently happens that 

 the calyx is not green but brightly coloured. In many 

 monocotyledons both calyx and corolla are coloured so 

 similarly that it is difficult to distinguish between them. 

 The flowers of some of our forest trees do not possess a 

 perianth at all, and in the flowers of others only one 



Fig. 46. Section of an ovule, mac, 

 megaspore or embryo -sac; oos, 

 ovum; pt, pollen tube. 



