86 



ROOTS 



IBd. 

 St. 



1. Outside examination. Describe the outer covering 

 (epidermis or skki). What is its color, texture, thickness, 

 and general appearance? Find the bud. Where is it lo- 

 cated? Of what is it com- 

 posed? Find the depressions 

 which are found on the sur- 

 face. Is there any system in 

 r Sec. Rt their arrangement? What is 

 seen projecting from some of 

 these depressions? (Secondary 

 roots.) 



2. Interior examination. Of 

 how many regions is the parsnip 

 composed ? How does the cen- 

 tral portion (central cylinder) 

 compare in color and structure 

 with the part underlying the 

 skin? (Cortex.) What sepa- 

 rates the cortex from the cen- 

 tral cylinder? 



Make very thin cross sec- 



FIG. 25. -Structure of a parsnip i{QW ftnd 1(X)k th h them 



root : a, skin ; 6, cortex ; c, sap 

 region ; d, central cylinder ; towards the light. Can yOU 



T. Bd., terminal bud ; St., stem ; discover any system in struc- 



Sec. Rt., secondary root. 



tural arrangement ? When pos- 

 sible, compare a parsnip two years old with one of one 

 year. 



Cut sections through the parsnip at the point where sec- 

 ondary roots are given off. Where is the origin of a secondary 

 root? Draw outside view, longitudinal and cross sections. 



Conclusion. Name the parts of a root and state where 

 each is located with reference to the others. 



