PRACTICAL WORK 327 



(6) Examine the radial longitudinal section, and draw under 

 the high power a sample of the following tissues : {a) phloem, 

 showing sieve tube (with sieve plate) and companion cell ; 

 (6) metaxylem, showing part of a pitted vessel with adjoining 

 parenchyma and fibres ; (c) protoxylem, showing spiral vessels 

 and adjoining thin-walled parenchyma. [It is necessary that 

 the section should pass radially through a bundle in order that 

 the above tissues should appear in it.] 



(7) Examine the demonstration showing positive phototro- 

 pism and the fact that the apex of the shoot is the light-perceiving 

 organ [capped Setaria seedlings are suitable] : also examples 

 of etiolated shoots to compare with examples grown in light 

 [bean plants are suitable]. 



