74 



PLANT BIOLOGY 



7. 



out the following parts: wall of ovary, small 

 objects within the ovary known as ovules. 

 These ovules develop into seeds. Describe what 

 you have done and tell what you have seen. 

 Make a drawing at least an inch in diameter of a 

 cross section of the ovary, labeling ovary wall, 

 ovules. 



8. (Optional.) Make a drawing (corresponding in size to that 

 called for in 7 above) of a lengthwise section of the 

 ovary to show wall of ovary, ovules. - Label. 



86. Pollination. We have learned in our study of flowers 

 that pollen is produced in the anther of the stamen, and ovules 



in the ovary of the pistil. 

 Before an ovule can develop 

 into a seed, however, certain 

 portions of a pollen grain 

 and of an ovule must be 

 combined. Pollen must, 

 therefore, be transferred 

 from the anthers to the 



pistils, and to this process is 



stigma - 



stamen 



petal 



ovary 



given the name pol- 



FIG. 24. Structure of a plum blossom. 

 (Bailey.) 



lination. We shall now learn by experiment some 

 adaptations of the pistil for receiving and holding ^ 

 the pollen. 



87. Experiment to show pollina- 

 tion. Laboratory Study No. 43. 



Rub a small brush or the end of 

 a toothpick over a stamen (e.g. 

 tulip, Easter lily, or gladiolus) which 

 has an abundance of pollen, and FIG. 25. -A pollen adhering 



.1 i i ,i 11 ,1 to stigma : B, pollen of plum 



then brush this pollen over the sur- escaping from the anther of 



face Of the Stigma. a stamen. (Bailey.) 



