ily, 1921] THE SEEDLING OF PHASEOLUS VULGARIS 359 



:/erage +.509 for primary double bundles and hypocotyledonary bundles, 

 -.629 for intercalary bundles and hypocotyledonary bundles, and +.813 

 !r total bundles and hypocotyledonary bundles. In the trimerous plants 

 lese correlations average +.381, +.238, and +.598, respectively. 



The correlations for normal plants are generally higher than those for 

 onormal plants. 



2. The correlation between each of the three classes of bundles at the 

 ase of the hypocotyl and the number of bundles in the central region of 

 ic epicotyl is low. The coefficients are sometimes positive and sometimes 

 egative in sign. On the basis of the data available it is impossible to 

 ssert that there is any correlation at all between the numbers of bundles 

 i these two regions. 



3. The correlation between the numbers of bundles in the central region 

 f the hypocotyl and in the central region of the epicotyl is likewise very 

 pw. The coefficients are generally not significant in comparison with 

 heir probable errors. If there be any correlation at all between the numbers 

 f bundles in these two regions it is very slight indeed. 



These results for correlation fully substantiate the conclusions drawn 

 n an earlier paper that there is a complete reorganization of the vascular 

 ysteni at the cotyledonary node. 



4. The correlation between the number of bundles (either hypocoty- 

 edonary or epicotyledonary) in siblings is, if it exists at all, very low. The 

 differentiation of the parent plants through either genetic or environmental 

 actors cannot, therefore, be considered to be the source of the variation 

 md correlation in bundle number demonstrated in this and in our preceding 

 paper. 



CONCLUSIONS 



These results, and others for which the reader must turn back to the 

 3ody of the paper, justify the emphasis at this point of the following general 

 inclusions: 



a. The vascular structures of the seedling are not constant but are 

 decidedly variable within the species. They show different degrees of 

 variability within the individual organism. 



b. Seedlings differing in external form are profoundly differentiated 

 in their internal anatomy. This differentiation is evident both in mean 

 number of bundles and in the degree of variability in bundle number. In 

 short, the external form and the internal structure of the seedling are highly 

 but not perfectly correlated. 



c. The different anatomical characters of the seedling are interrelated 

 with varying degrees of intensity. Between some there is a very strong 

 correlation, but between others practically none at all. 



The quantitative measurement and interpretation of such relationships, 

 by means of the biometric methods hitherto little applied in the field of 

 vascular morphology, will make possible material advance in the investiga 

 tion of the fundamental problems of morphogenesis. 



