A MANUAL OF BOTANY 53 



Study a cross section of the ovary. Into how many com- 

 partments (cells) is it divided? What do you observe in 

 each cell ? These structures are ovules. Examine very 

 carefully and determine, if possible, their point of attach- 

 ment (placenta) to the ovary. It may be on a central axis 

 (axial), or on the ovary wall (parietal). 



These ovules are really megasporcuKjia, each containing 

 one megaspore. The ovules eventually become seeds by a 

 process called fertilization. Look this subject up in your 

 textbook and refer back to the willow. Draw a cross 

 section of the ovary (m), naming all the parts. If the ovary 

 walls are, as is usually considered the fact, made up of 

 peculiarly modified leaves (carpels), how many can you 

 decide there are in the trillium ? Where are the ovules 

 attached with reference to the leaf margins or midribs ? 



Lily family. The trillium is an example of the lily 

 family, which contains many showy or useful plants, as 

 the tulip, hyacinth, lilies, onions, etc., and is one of the 

 large families of monocotyledons. Some authors divide the 

 family into several smaller families, in which case the Tril- 

 lium is placed in either the Lily of the Valley or the 

 Trillium Family. 



Practical work. The cultivation of the Bermuda, Spanish, 

 or other onions for the mature bulbs, and the immense 

 amount of green onions grown, show the importance of this 

 famil}^ as a vegetable producer. Leeks, garlic, chives, and 

 shallots are other related forms. 



Asparagus is largely grown for commercial purposes, to 

 be used fresh or canned. 



In certain regions tulips, Bermuda lilies, and hyacinths 

 are grown in immense numbers to supply the demand for 

 the flowering bulbs. 



A large number of species are grown by florists and in 

 home gardens. A few are valuable in medicine. 



An onion venture. A young man planted one acre of 



