Studies of Selected Spermatophytes. 239 



f erent 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 visit these flowers ? Are 

 the maple flowers adapted to cross pollination ? 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.) 



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 



