LABORATORY AND FIELD WORK 411 



14. Make a list of the kinds of pines and other gymnosperms 

 that you find growing in your locaHty. Which of them are native 

 plants? Which have been introduced from other parts of the 

 world ? 



Chapter XII 



1. Watch the growth of the stem of a climbing bean from day 

 to day and observe how it climbs. Compare this with the way in 

 which tall peas and sweet peas support themselves in an upright 

 position. 



2. Where are branches borne? Do they twine like the main 

 stem ? Do the branches themselves branch ? 



3. How does the blade of a bean leaf compare with that of a 

 leaf of a cucumber or squash? What is the arrangement of the 

 veins in a leaflet ? Draw a leaf and a portion of the stem or branch 

 to which it is attached, naming the parts of the leaf. Is there a 

 bud in the axil of the leaf ? 



4. Observe the position of the leaves and leaflets after dark. 

 Compare it with their position during the day. Can you find 

 other plants growing either in- or out-of-doors that show such 

 differences in the positions of their leaves by day and by 

 night ? 



5. What is the form of the root system of the bean ? Can you 

 recognize the primary root? Do the roots branch? Notice es- 

 pecially the small swellings that are likely to occur at various 

 places on the roots. What organisms live in the swellings ? Hov/ 

 are th£se organisms important to the bean plant? Draw a small 

 portion of the root system, showing some of the swellings. 



6. In a cross section of the stem can you make out epidermis, 

 cortex, vascular bundles, and pith? Compare the arrangement 

 of the vascular bundles with their arrangement in the pine stem. 

 In what part of each bundle is the wood? The bast? Draw a 

 portion of the section. 



7. Study a cross section of a leaf. Notice the upper and the 

 lower epidermis. Are the cells of the layer just below the upper 

 epidermis different in any way from the other cells of the leaf? 

 What kind of cells make up most of the thickness of the leaf? 

 Are there spaces between the cells ? In what cells do you find the 



