112 THE BIOLOGY OF A PLANT. 



water, and kept wet during the cutting. Mount the section in 

 water, and, using a low power, observe the general arrangement 

 of the three great TISSUE-SYSTEMS (p. 72), and compare Figs. 33, 

 35-41. 



2. In a thin transverse section study with a higher power the 

 component tissues and cells of each system, as follows : 



a. EPIDERMAL SYSTEM. 



I). FUNDAMENTAL SYSTEM. 



a. Fundamental parenchyma, 

 ft. Sclerotic parenchyma, 

 y. Sclerotic prosenchyma. 



C. FlBEO-VASCULAR SYSTEM. 



a. Bundle-sheath. 



ft. Phloem-sheath. 



y. Bast-fibres or phloem-prosenchyma. 



8. Sieve-tubes. 



e. Phloem-parenchyma. 



C. Tracheids. 



ij. Vessels. 



V. Wood-parenchyma. 



3. Repeat 1 and 2, using instead of a mature part of the 

 rhizome a section taken -J inch from the tip of an apical bud. 

 Compare these sections with the former and report your results. 



4. With a knife-blade or a "lifter" transfer a thin section to 

 a solution of iodine in a watch-slass. Turn the section once or 



^j 



twice to insure its thorough staining ; transfer after a few minutes 

 to a larger dish of water to remove the excess of iodine ; mount 

 in water, or dilute glycerine (glycerine 1 part, water 2 parts), and 

 study carefully with your highest power the distribution of 

 starch and protoplasm in the several systems, tissues, and cells. 



Prepare tables showing (#) the contents of the tissues and (7j) 

 their relative vitality or activity as indicated by their contents 

 ;iml the nature of their walls. 



5. Stain other sections in acidulated solution of aniline chlo- 

 ride, mount as before, and study. (Cf. B. 3.) 



6. Make a transverse section of a root, and compare it with 

 that of the rhizome. 



