PROBLEM 3. How Co?nplex Fla?its Reproduce 4<^f 



9. Compare the development of the embryo in the plant with that in the 

 animal. What is endosperm? Name a seed which has no endosperm 

 and one which has a large endosperm. 

 ID. What is a fruit? How mav fruits and seeds be dispersed? 



11. Starting with a plant in flower describe the life cycle to the point 

 where the new plant is ready to reproduce. 



12. Show how there is a regular alternation of asexual reproduction and 

 sexual reproduction in the fern. 



13. Which parts of the flower can be thought of as producing asexual 

 spores? 



14. What is meant by vegetative propagation? To what process in animals 

 is it similar? Explain what is meant by a slip or cutting, a runner, a 

 layer. Name a plant in each case. 



15. Name other methods of vegetative propagation, with an example of 

 each. 



16. Explain how fruits can be artificially made to develop without seeds. 

 When they develop naturally without seeds, state which step in the 

 process of reproduction may fail to occur. Give examples. 



Exercises 



1. What is the structure of the seed? Soak dried lima bean (or kidney 

 bean) seeds overnight. Notice the scar {hilum) on the side of the bean. 

 What causes the scar? If you press the bean gently you can see a tiny 

 hole at one end of the scar. This opening is the uiicropyle. You will un- 

 derstand later what must have once entered through this micropyle. Re- 

 move the seed coats and carefully separate the two large, fleshy, leaflike 

 structures. These are the cotyledons, or seed leaves. They are attached to 

 the hypocotyl. Describe it. Describe the phmmle which lies between the 

 cotyledons. Into what do hypocot}d and plumule grow if the seed is 

 allowed to sprout? Name the three parts of the baby plant. What might 

 be the function of the fleshy cotyledons? Test the cotyledons for starch 

 and protein. What do you find? 



2. What happens to the seed under favorable conditions? Line a bat- 

 tery jar or fruit jar with moist blotting paper and place a few soaked 

 lima or kidney beans between the paper and the jar. Keep a record of the 

 development of the seeds from day to day. Which part first bursts 

 through the seed coats? Plant some seeds in moist sawdust. Plant them 

 about an inch below the surface. Which part first appears above ground? 

 How is it kept from being injured as it pushes through the sawdust (soil)? 



3. What are the parts of a flower? Study a tulip, gladiolus, or some 

 other simple flower in season. Use the description in the text as a guide. 

 Draw one or several diagrams of your flower and label all of the parts. 



4. What is the structure of a pollen grain? Rub the ripe anthers of sev- 

 eral different flowers on separate slides, add water and cover slips, and 

 examine under the low power. How do the pollen grains differ? 



