104 VARIATION AND DIFFERENTIATION IN CERATOPHYLLUM. 



and III, the frequency of the various leaf-numbers for successive whorls, 

 proceeding by groups of 10 whorls. Calculating the standard deviation 

 {(Tn.) for each array of this table, and dividing it in each case by the 

 standard deviation M of all main-stem whorls, we have the results 

 shown in table 52. 



Table 52.— Variability of successive main-stem whorls. 



The data in this table are shown graphically in fig. 23. 



i-10 II-EO 21-30 31-40 41-50 51-60 61-70 71-80 81-90 

 Whorl 

 Fig. 32.— Scedastic curve for whorls on main stem. Seiles I, 

 II, and III combined, 



