156 MORPHOLOGY AND LIFE HISTORY 



its form and surface characters, and note the num- 

 ber, and place and mode of attachment of the large 

 megasporangia (ovules) . Note their color. Draw, 

 natural size. 

 4. Do you find smaller, undeveloped ovules? These 



have probably not been pollinated. 

 /. The Young < Ovule: 



1. Is the ovule enclosed by the carpel, or is it naked? 

 State why Zamia is classed as a gymnosperm. 



2. At the end of the ovule, opposite its point of attach- 

 ment, note the small, often slightly elevated, dark 

 spot, which marks the place of the micropyle (small 

 gateway), through which the pollen-grain passes 

 in order to reach the pollen-chamber within. This 

 process is called pollination. In Zamia, pollination 

 occurs about Jan. i. 



3. Remove an ovule, carefully noting where and how 

 it is attached to the carpel. -M 



4. Describe its surface and shape. How may the 

 latter, in part, be accounted for? At the end 

 opposite the micropyle observe the scar (hilum), 

 where the ovule was attached. Draw. 1 



5. With the scalpel, make a slight longitudinal incision 

 of the integument (wall) of the ovule, being careful 

 not to cut too deeply, so as to injure the delicate 

 structures within. Describe the character of the 

 tissue of the integument. 



6. The tissue next within the integument is the 

 nucellus, or megasporangium. The integuments 

 are outgrowths of the nucellus. 



1 Arrange all the drawings, showing the ovule at different ages, serially, 

 on a new sheet of drawing paper, so as to facilitate the comparison of the 

 different stages, and to show at a glance the changes which the different 

 parts undergo. 



