On Correlation in the Growth of Roots 
and Shoots 1 . 
BY 
L. KNY. 
E VERY multicellular plant-body — the cells of which are 
not loosely connected as are those of a colony, 
but, on the contrary, maintain a mutual interchange of 
material and present a diversity of complementary functions 
— constitutes a single and complete whole. In the lower 
plants this unity is not fully attained, for the independent life 
of each individual cell still asserts itself too strongly : here 
each cell possesses the capacity of performing all, or at any 
rate many, of the vital functions of the organism, and con- 
sequently one part of the plant can continue to live inde- 
pendently of another. But in plants, such as the Phanerogams, 
where the physiological division of labour reaches its highest 
pitch, this is not the case : to such plants the foregoing 
proposition is more especially applicable. Here root, stem, 
and leaf mutually presuppose each other. A root no longer 
in structural connexion with its corresponding shoot, clearly 
lacks all the conditions for prolonged existence ; for it can no 
longer get rid of the materials which it absorbs from the 
soil, nor does it receive supplies of organic substance for its 
nutrition. Similarly, stem and leaf can only continue to 
function normally so long as the regular interchange of material 
between them and the other members of the plant with which 
they are in organic connexion is maintained. 
Such considerations as these justify the question raised by 
1 Read before Section D of the British Association, Oxford, August n, 1894. 
[Annals of Botany, Vol. VIII. No. XXXI. September, 1894.] 
