TRILLIUM RECURVA TUM. 199 



development of which gives rise to the 

 wrinkling. 



b. The median large-celled or parenchyma region. 



c. The central or fibro-vascular region, in which may 

 be detected the large openings of four or five 

 tracheary vessels. 



Mount a longitudinal section through the center of the 

 root and notice 



6. The several regions as before. 



7. The depth of the surface wrinkles. 



8. Diagram both the transverse and longitudinal sections. 



C. THE ROOTSTOCK (Subterranean Stem). Note 



1. The shape and thickness. 



2. The succession of nodes and inter nodes. 



a. The number in an unbroken rootstock. 



b. The scars of former branches, and the varying 

 number of intervening nodes. 



c. The irregular growth of the internodes. 



3. The prevailing number of roots from each node. 

 Mount a transverse section ; notice 



4. 1\& three parts : 



a. The extremely narrow brownish cortical region, 

 forming the boundary of the section. 



b. The great mass of the stem, whitened with the 

 reserve food material. In thin parts of the sec- 

 tion, where the food material has been washed out 

 in mounting, note 



i. The delicate colorless tissue, fundamental par- 

 enchyma. 



