40 



Elementary Work in Botany. 



that formed the preceding 



Fig. 27. Diagram showing the seasonal 

 growth of an exogen. a. Bud at the end of the 

 first season's growth, the wood and bark of 

 which is shaded, b. Bark of the second season's 

 growth enclosed below the scars (j) of the first 

 season's bud scales by the bark of the first 

 season (c). d. Wood of the first season, e. 

 Wood of the second season. A. Cross-section 

 hear the base. B. Cross-section near the end of 

 the first season's growth. 6'. Cross-section just 

 at the beginning of the second season's growth 

 (the pith wanting). 



scars which marks the end 



season, the nearly tnbular 

 growths would appear in 

 a cross-section as rings. 

 You have estimated the age 

 of your specimen by the 

 bands of scars produced by 

 the scales of terminal win- 

 ter buds. If your specimen 

 bears two such bands, you 

 have decided that the base 

 contains pith and a layer 

 of wood made three years 

 before its outer layer was 

 formed. Do the rings of 

 the section confirm your 

 decision ? Make a section 

 half an inch below the base 

 of the next growth and 

 compare with one made just 

 above the base. Why do 

 they show the same number 

 of rings ? To understand 

 this you must imagine the 

 condition at the end of the 

 first season's growth. There 

 was a terminal bud where 

 now you find the band of 

 of the first growth and the 



