116 VARIATION AND DIFFERENTIATION IN CERATOPHYLLUM. 



THE POSITION OF BRANCHES. 



In the last section the ordinal position with reference to the proxi- 

 mal end of the axis of the nodes at which lateral branches originate 

 was studied in order to get light on another question. I wish now to 

 consider on its own account some other phases of the problem of branch 

 production. 



The first question which we may consider is as to where, on any given 

 axis of the plant, branches begin. That is, at what node, counting 

 from the proximal end of an axis, does the most proximal branch on 

 that axis appear. And what degree of variation is there in this mat- 

 ter? The frequency distributions giving data on the point for Series 

 I to IV are exhibited in table 60. The data are for the position of the 

 most proximal secondary branches. 



Table 60.— Frequency distribution for positions offirsf branches (secondaries). 



Node of primary branch 

 at which the first 

 secondary branch 

 develops. 



9 



10 



11 



12 



13-18. 

 19 



Total. 



'Throughout the section of the paper the most proximal branch on any axis of the 

 plant will be designated as a "first" branch, tlic next branch distad of this as the "sec 

 ond" branch, and so on. (t;f. tig. 25, infra.) 



Calculating from this table I find for the means, medians, and stand- 

 ard deviations the following values: 



Table Q1.— Constants for variation in position of "first" secondary branches. 



