98 FUNCTIONS OF REPRODUCTIVE PARTS 



in order to withstand the action of the digestive juice of 

 animals which eat the fruits. 



SUMMARY OF THE FUNCTIONS OF PARTS OF 

 FLOWERS, FRUITS, AND SEEDS. 



1. The calyx usually protects the young flower bud {e.g. 

 Poppy). It may also serve as a means of attracting insects 

 by its colour {e.g. Clematis), or act as a factory {e.g. Mallow), 

 or as a receptacle for honey {e.g. Wallflower). Sometimes the 

 calyx aids in the dispersal of the seeds by the agency of the 

 wind {e.g. pappus of Compositse). 



2. The corolla serves to attract insects which will effect cross- 

 pollination. It may further bear nectaries {e.g. Buttercup). 



3. The androecium. — The pollen pollinates the flower, 

 and is indispensable for the production of seed. The 

 anther manufactures the pollen. The filaments bring the 

 anthers into the position which will lead to cross-pollination 

 by wind or insects, or to self-pollination. As good ex- 

 amples, illustrating the fact that the length of the filaments 

 is to be explained in accordance with the method of pollina- 

 tion, we have but to compare and contrast the flowers of the 

 Primrose, of Grasses, and the cleistogamic flowers of the Violet. 

 The time and direction of dehiscence also are related to the 

 method of pollination; we note, for instance, the introrse 

 dehiscence of the Violet and of Composites, the extrorse dehis- 

 cence in the Buttercup when the flower opens. 



4. The gynsecium. — The embryo-sac in each ovule is the 

 region in which the embryo and its food (endosperm) arise. 

 The ovary protects the ovules. The stigma receives the pollen- 

 grains. The style raises the stigma to the proper height so as 

 to bring about cross-pollination or self-pollination. The size, 

 shape, and time of ripening of the stigma and style bear relation 

 to the method of pollination (see Grasses, Compositse, Violet). 



5. Sugar.— Sugar is excreted in flowers in order to attract' 

 insects which will effect cross-pollination. Sugar is manufactured 

 in many fruits, and is responsible for their sweetness of flavour, 

 in order to allure animals (mainly birds in this country) which 

 will disperse the seeds. 



6. Pericarp. — The pericarp protects the seeds and often 

 facilitates their dispersal. Often it is brightly coloured so as 

 to attract the notice of animals. It may or may not dehisce. 



