Studies of Selected Spermatophytes. 239 



ferent trees and find whether staminate, pistillate, and 

 perfect flowers occur. Make longitudinal diagrams of 

 the different kinds of flowers. Draw a stamen and a pistil 

 on a large scale as seen under a lens. Study with a lens 

 and show by a drawing the position and character of the 

 stigmatic surface. Do insects \-isit these flowers .' Are 

 the maple flowers adapted to cross polUnation ? What is 

 the advantage in this case in having the flowers appear 

 before the leaves ? Follow the development of the pistil 

 to the mature fruit and state what changes the pistil under- 

 goes in ripening. What part of the pistil forms the wings.' 

 Do all of the ovules become seeds as a rule? 



Viola. (Obtainable species.) — Violet. 



Study all obtainable species of the violet. State the 

 character of the habitat of the different species^ studied. 

 Draw a typical leaf. How are the leaves rolled up in the 

 bud .' Draw a rootstock. What evidence do you find that 

 it is morphologically a stem .' What is the nature of the 

 roots .' Draw a flower in right position with reference to 

 the vertical. Study the face of a flower. Is there an 

 opening through which an insect can enter or thrust its 

 proboscis .' Is pollen visible .' Dissect a flower. What 

 part constitutes the spur.' The horn-like projections from 

 the two lower stamens secrete the nectar and pour it into 

 the spur. Do you find nectar there ? Do the anthers 

 dehisce toward the outside or inside .' What becomes of 

 the pollen after the anthers break open } What is the use 

 of the scale-like tips of the stamens .' Is the stigma so 

 shaped and situated as to receive self pollen ? Sum up 

 those facts about the flower which relate to its pollination. 

 How are the pollen and nectar protected against waste .' 

 As the flower is constructed, would it be just as well for it 



