No. 607] NUMBERING PLANTS IN PEDIGREE CULTURES 435 



is given the number of the notebook page on which its 

 progeny are to be described, preceded by two figures in- 

 dicating the year in which those progeny are grown ; e. g., 

 06230 is a parent whose progeny are grown in 1906 and 

 described on p. 230 of the 1906 notebook. Only parental 

 and grandparental numbers (e. g., 0557.230 for the case 

 just mentioned) are shown at the head of each notebook 

 page, but these numbers permit ready reconstruction of 

 pedigrees from the pages indicated. The labels bear only 

 the parental number. 



In Shull's scheme, then, there is no cumulation beyond 

 the second generation, even in the numbers as written in 

 the notebook. The numbers would include 4 to 8 figures 

 (e. g., 083.7, or 05157.230) in the notebook and 3 to 5 fig- 

 ures (e. g., 097, or 06230) on labels. In the scheme here 

 suggested there is a continuous cumulation ; a plant of the 

 second or Fj generation is usually represented by 3 to 7 

 letters and figures (e. g., 5b-8, or 32ba-251), and after 

 from 2 to 4 more generations the numbers begin to be de- 

 cidedly unwieldy. The greater inconvenience and danger 

 of error in copying these larger numbers would seem, 

 however, to be largely offset by the growing familiarity 

 to the worker of the earlier part of a pedigree, and by the 

 identity of the temporary and permanent designations of 

 individuals. Further, the page-to-family feature would 

 be inconvenient in some cases, where several or many 

 actual pages are given to one progeny lot and so would 

 require the same number. 



With a cumulative system, the simple device of using 

 temporary yearly lot numbers on individual labels will 

 obviate the necessity of writing a long pedigree number 

 for each plant. If the full number is written in the note- 

 book and on each lot label, together with the lot number 

 (e. g., LI = 16aa-6-3-44-l&-3), and the latter alone on the 

 individual labels if these are used, much work can be 

 saved. In an extreme case, the parents belonging to a 

 given series which are included in a given culture can be 



