Suggestions for Laboratory Work to Precede Chapter Eleven 



1. Sketch cross sections of some monocot stems like com, 

 bamboo, asparagus, lily, or wheat. Note particularly the arrange- 

 ments of the bundles. Cut a longitudinal section through a node, 

 and note how the bundles unite in the node. 



2. Sketch a cross section of a peach branch that is an inch or 

 two in diameter. Note pith, wood, bark, cortex, cortical paren- 

 chyma, cork, cambium, annual rings, and pith rays. 



3. Sketch a cross section of a pine stem and note the parts, as 

 in the peach. 



4. With a microscope, examine thin sections of monocot, dicot, 

 and conifer stems, and note differences in the structures of the 

 bundles. 



5. Examine sections of tree trunks and determine the number of 

 annual rings in the sapwood and in the heartwood. What fraction 

 of a large tree trunk is alive ? 



6. Bring a branch of a tree to the laboratory and try to set up 

 cleft and whip grafts. Also try to set a bud. Repeat the opera- 

 tion on trees out of doors and see whether or not the cions will live. 



7. Show the region of growth by marking the upper end of a 

 stem with transverse lines at equal intervals. 



8. Show the effect of gravity on the direction of growth by 

 changing the position of a growing stem with reference to gravity. 



9. Show the effect of light on the direction of stem growth by 

 placing a plant where hght can reach it from only one direction. 



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