176 LABORATORY AND FIELD EXERCISES 



c. Pollination. 



1. What are the special devices for securing pollina- 



tion ? To determine this point study flowers of 

 different ages and note the relation of the differ- 

 ent lengths of stamens to the stigmatic surface. 

 Does this relation change as the flower matures ? 



2. Construct outline drawings to illustrate any devices 



for self-pollination, close-pollination, or cross- 

 pollination which you discover. 



d. Fruit and seed. Study and classify fruits 011 one or 



more species of the Qruciferae. Construct a diagram 

 of the fruit to show its method of dehiscence. 



3. Seasonal life. Study the seasonal life of some of the more 



important cultivated species of the Cruciferae in the 

 field and by consulting text references. See, for example, 

 Bailey's "Encyclopedia of Horticulture," Robbins's 

 " Botany of Crop Plants," and Sargent's " Plants and 

 their Uses." 



a. Are the members of the family mainly annuals, bien- 



nials, or perennials ? How do the biennials and peren- 

 nials pass the winter ? 



b. Construct a series of diagrams to illustrate the seasonal 



life of one important commercial variety of the Cru- 

 ciferae. Consult the text, Part I, on the seasonal life 

 of the bean, clover, and locust. 



4. Commercial importance. Make a list of the more important 



species of Cruciferae and indicate the use of each species. 



5. Analysis. Analyze species of the Cruciferae^ recording 



the family, species, and common name. 



6. Distinctive characteristics. Summarize under habit, repro- 



duction, and seasonal life. The above data may be 

 recorded on a Species Eecord or a Family Eecord sheet 

 if desired. 



