VARIATION IN DIFFERENT PORTIONS OF PLANT. 



35 



It is evident from these tables that division of the main stem occurred 

 relatively infrequently in our material. All plants of Series II, V, and 

 VI and and three out of five plants of Series I had the main stem undi- 

 vided. Plant 1, Series III and both plants of Series IV had long 

 secondary main stems. In these plants the main stem proper was very 

 short, bearing only a few whorls. In the case of plant 2, Series IV, 

 there were no unmutilated whorls on the main stem below the point of 



Table 11. — Frequeiicy distributions for variation in leaf-number of whorls on 

 secondary main stems. 



Series. 



III.., 



IV 



Plant. 



All plants, 



All plants. 



Table 12.— Frequency distributions for variation in leaf-number oftvhorls on 



tertiary main stems. 



division. The distributions exhibit even on casual inspection a marked 

 difference from what has been shown to be characteristic for the varia- 

 tion of whorls on branches. - These differences are brought out in a still 

 more striking way by the constants of the distributions, which are given 

 in table 13. 



Now, I think it is perfectly obvious if we compare the values given 

 in this table with those for the "all-branch" distributions given in table 

 8, or with those for the primary, secondary, or tertiary branches given 

 in tables 15, 18, and 23, infra, that the whorls on those divisions of the 



