xv THE DEVELOPMENT OF THE FLOWER 205 



In the embryo-sac the parts present are 



(a) Egg apparatus synergidae, oosphere ; (b} antipodal cells ; (c) em- 

 bryo-sac nucleus ; (d) protoplasm. 



The first part of the gynoecium to be developed is the stigma. This 

 is carried up by the growth of the tissue beneath. The ovary is the last 

 part to appear. The union of the carpel or carpels forms the ovary. 



The kinds of ovules are as follows 



(i) The orthotropous ; (ii) the anatropous ; (hi) the campylotropous. 



QUESTIONS ON CHAPTER XV. 



(1) State what you know about the development of (a) the calyx, 

 (d) the corolla, (c) the stamens, and (d) the pistil, in any flower of your 

 own selection. 



(2) What is the structure of (a) the calyx, and (b) the corolla of any 

 flower ? Of what use are they to the plant ? 



(3) Describe the structure of an anther and of a pollen grain. (1890.) 



(4) What is pollen? Give an account of its development and its 

 function. (1893.) 



(5) How are the pollen grains set at liberty? Give examples. 



(6) Describe the contents of the embryo sac at the time when fertil- 

 isation is about to take place. (1891.) 



(7) Give a description of the successive stages in the development of 

 the embryo-sac in any plant. (1894.) 



(8) Explain the use of the stigma, and describe the structure of the 

 stigma of any flower you may select. 



(9) Describe, giving an example of each, the anatropous, the ortho- 

 tropous, and the campylotropous ovule. (1898.) 



(10) What is a pollen tube? How is it produced, and what is its 

 use? 



(n) Of what parts does an ovule consist? Where are ovules found, 

 and how are they held in position ? 



( 1 2) Explain with diagrams the following terms anatropous, tapetum, 

 synergiclae, antipodal cells. 



