200 MORPHOLOGY AND LIFE HISTORY 



(a) Its outline. Each of the lobes represents the 

 section of one of the carpels (megasporophylls), 

 which together compose the tri-carpellate, 

 compound ovary. 



(b) The number of compartments ("cells"). Do 

 the septa (walls) that separate them meet in 

 the center? Compare the number of cells with 

 the number of carpels. 



(c) The placentae (sing., placenta), or surfaces of the 

 septae to which are attached. 



(d) The ovules. Do the ovules lie in a vertical or 

 in a horizontal plane? Are they few or numer- 

 ous? In Trillium the ovules are borne on 

 parietal placentae. 



(e) The funiculus (stalk) by which the ovule is 

 attached to the placenta. Observe (using 

 magnifier that the ovules have curved through 

 1 80, bringing then* apical (micropylar) ends to 

 their base or point of attachment to the fu- 

 niculus. They are thus anatropous ovules. 



(/) Make a drawing, 4 cm. in diameter, showing 



the ovary (and ovules) as seen in cross-section. 



4. Histology of the anther. Development of the pollen. 



(a) Use prepared slides. The sections on these 

 slides are triple-stained with safranin, gentian- 

 violet, and orange. By this means the various 

 parts of the cell are given different colors, the 

 cytoplasm a grayish tinge, the nucleolus and 

 chromatin threads in the nucleus red, starch 

 grains a deep blue. 



Using slides showing the microspore-mother-cell 

 stage of Lilium canadense, or other convenient 

 plant, 



(b) Observe the outline of the section as a whole. 



