CORRELATIONS BETWEEN ANATOMICAL CHARACTERS IN 
THE SEEDLING OF PHASEOLUS VULGARIS 
J. Arthur Harris, Edmund W. Sinnott, John Y. Pennypacker, and G. B. Durham 
(Received for publication January 17, 1921) 
Introduction 
In an earlier paper^ we traced the course of the vascular bundles through- 
out the dimerous and trimerous seedlings of Phaseolus vulgaris and measured 
the variation occurring at different levels. 
The chief results of that paper were (a) the demonstration of the pro- 
found differentiation of dimerous and trimerous seedlings in their internal 
(vascular,) as well as in their external characters, {h) the demonstration 
that the number of bundles at a given level in the seedling is a highly vari- 
able rather than a constant character, and (c) that the various organs or 
regions of the plant body (particularly, in the present case, those which 
are separated by the vascular anastomoses at the cotyledonary node) 
differ widely in the magnitude of their variability as to bundle number. 
In this paper we propose to consider in quantitative terms the degree 
of interrelationship between the vascular structures in the different regions 
of normal and abnormal seedlings. The results of such an investigation 
will evidently be of considerable morphological interest, since many of 
the problems of organic form are fundamentally problems of correlation. 
Two morphological problems at once present themselves for considera- 
tion : 
First, is there a high correlation between the vascular topography of 
two different levels of the same internode, i.e., is the number of vascular 
bundles constant throughout the length of an internode or is there more 
or less extensive splitting or anastomosis within the length of such a con- 
ventional morphological unit? 
Second, is there a definite correlation between the vascular topography 
below a node and the vascular topography above it, or is the vascular 
system so fully reorganized at the nodal anastomosis of bundles that, in 
bundle number, successive internodes are practically independent of one 
another? 
With the present material, these questions may be answered by de- 
termining the coefficients of correlation for bundle number between (i) 
the base and the mid-region of the hypocotyl, and (2) between the various 
levels 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. 
The vascular anatomy of dimerous and trimerous seedlings of Phaseolus vulgaris. Amer. 
Jour. Bot. 8: 63-102. 1921. 
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