THE FLOWERING PLANT FLOWEES 375 



the various structural modifications which the 

 parts undergo in each flower. Make a diagram 

 of a cross - section of each flower, showing the 

 number and position of all the parts, also a draw- 

 ing twice natural size of one of each of the floral 

 organs showing its shape and structure. Examine 

 old flowers and young fruits of each plant, and 

 trace the changes which take place in the parts 

 of the flower. In which flowers do you flnd 

 organs of the same kind grown together, illus- 

 trating coalescence? In which, organs of dif- 

 ferent kinds, adnation? In which do you find 

 the parts of any group of organs unlike in shape, 

 examples of irregularity? Endeavor to ac- 

 count for the various shapes, colors, arrange- 

 ment of parts, etc., found. In what way does 

 a flower resemble a bud? A leafy branch? 

 "Which of the flowers illustrate symmetry, i. e., 

 have the same number of .parts in each group of 

 organs, or have a certain number in some groups 

 but a multiple of that number in the remaining 

 groups ? 



MiorosGopic Structure. 



Section the pedicel of the flower and compare 

 its tissues, vascular bundles, etc., with those of 

 the stem and of the petiole. Examine the sepals 

 and petals and compare with one another and 

 with leaves. Draw all of the sections. Study 

 the structure of the filament and anther and ex- 

 amine the pollen. What is the shape of the 

 pollen grains? Color? Do they bear any mark- 

 ings or projections on the surface? Do you find 

 variations in any of these particulars ? What is 



