100 ABSORPTION OF WATER AND MINERALS 



3. Make permanent double-stained mounts from paraffin 

 material of Cuscuta parasitic on balsam or on any other host 

 suitable to paraffin sectioning. Study with low and high powers. 

 Note whether the water and food-conducting tissues of the 

 parasite are in organic union with the corresponding tissues 

 of the host. Can you tell precisely where the tissues of the 

 parasite leave off and those of the host begin? and if so, how 

 can it be told? Show by a diagrammatic drawing the host and 

 parasite, and on a larger scale draw a few cells of the phloem 

 and xylem of the host and corresponding cells of the parasite 

 joining these. 



4. Study free-hand cross sections, or paraffin sections done 

 into permanent mounts, of Tillandsia usneoides. Mount free- 

 hand sections in dilute glycerine. Make a drawing through a 

 scale showing its relation to the tissues of the stem. 



