[Reprinted from the AMERICAN JOURNAL OF BOTANY, 8: 339-365 July, 1921.] 



CORRELATIONS BETWEEN ANATOMICAL CHARACTERS IN&quot; 

 THE SEEDLING OF PHASEOLUS VULGARIS 



ftpTHUR HARRIS, EDMUND W. SINNOTT, JOHN Y. PENNYPACKER, AND G. B. DURHAM. 

 (Received for publication January 17, 1921) 



INTRODUCTION 



In an earlier paper 1 we traced the course of the vascular bundles through- 

 ^j the dimerous and trimerous seedlings of Phaseolus vulgaris and measured 

 o variation occurring at different levels. 



1 The chief results of that paper were (a) the demonstration of the pro- 

 ildnd differentiation of dimerous and trimerous seedlings in their internal 

 (&amp;gt;fscular) as well as in their external characters, (b) the demonstration 

 jtlit the number of bundles at a given level in the seedling is a highly vari- 

 kje rather than a constant character, and (c) that the various organs or 

 rdions of the plant body (particularly, in the present case, those which: 

 jaj separated by the vascular anastomoses at the cotyledonary node); 

 dfer widely in the magnitude of their variability as to bundle number. 



I In this paper we propose to consider in quantitative terms the degree 

 ofnterrelationship between the vascular structures in the different regions 

 ojnormal and abnormal seedlings. The results of such an investigation 

 ?wl evidently be of considerable morphological interest, since many of 

 tfe problems of organic form are fundamentally problems of correlation. 



| Two morphological problems at once present themselves for considera- 



pK 



First, is there a high correlation between the vascular topography of 

 to different levels of the same internode, i.e., is the number of vascular 

 bridles constant throughout the length of an internode or is there more 

 ojless extensive splitting or anastomosis within the length of such a con- 

 vutional morphological unit? 



.Second, is there a definite correlation between the vascular topography 

 blow a node and the vascular topography above it, or is the vascular 

 sxtem so fully reorganized at the nodal anastomosis of bundles that, in 

 bpdle number, successive internodes are practically independent of one 

 anther? 



With the present material, these questions may be answered by de- 

 temining the coefficients of correlation for bundle number between (i) 

 * base and the mid-region of the hypocotyl, and (2) between the various 

 teels of the hypocotyl and the mid-region of the epicotyl. It is these 

 Harris, J. Arthur, Sinnott, E. W., Pennypacker, John Y., and Durham, G. B. 

 vascular anatomy of dimerous and trimerous seedlings of Phaseolus vulgaris Amer 

 Jcr. Bot. 8: 63-102. 1921. 



339 



