X. ROOTS 



Root Structure 



Suggestion. Prepare a number of bean, pea, and corn 

 seedlings by carefully digging them up and washing away 

 any clinging soil particles ; or use a pocket garden. Find 

 the long main root (primary root). Of what is it the con- 

 tinuation? What is its normal direction of growth? Find 

 the other roots (secondary roots) which branch from the pri- 

 mary root. What is their normal direction of growth? 

 Account for the difference in direction between primary and 

 secondary roots. Find other branches (tertiary roots or 

 rootlets). What is the general direction of all the roots? 

 Is there any definite system of arrangement in the branch- 

 ing of roots? Have they any definite shape? Do they 

 seem to be limited in the length to which they grow? Look 

 for root hairs near the ends of young roots. Do they occur 

 at the very tip of a root ? Are they seen along the surfaces 

 of old roots ? 



74. ROOTS 



Object. To find out the parts of a root. 

 Apparatus. A parsnip or carrot, and a sharp knife. 



Method. Examine the root, first giving attention to 

 the external appearance. Afterward make sections length- 

 wise through the center and crosswise at different points 

 so as to see the gross structure. 



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