500 MISS ISABEL MCCLATCHIE ON 
Their development, both in these cases and in those of the wounded plants 
described below, seems to be an abortive attempt to compensate for the inter- 
ference with the water-supply, and with the translocation of elaborated food. 
It is possible, too, that the nodal bending of the plants in which adventitious 
roots are developed may also cause such compression of the food-channels as 
to induce accessory root-formation, although, in view of the relatively slight 
amount of bending in many cases, this is distinctly problematical. The cases 
described by Detmer * of root-development in willow shoots in which partial 
ringing has been practised, and in shoots of Nerium Oleander and Mirabilis 
Jalapa, which possess accessory medullary bundles, seem to offer a partial 
Fra. 8.—Plant showing characteristic slitting of the internode. Adventitious roots have 
developed from an upright stem at the base of the succeeding internode. 
parallel at least to the conditions indicated as obtaining in Impatiens Royler, 
although the object of the experiments upon these plants is to demonstrate 
the stimulus to root-formation below the seat of injury, provided that suffi- 
cient tissue is provided for the translocation of proteid material. 
Е. In wounded plants. 
Many plants are found which have suffered some accidental injury, and it 
is interesting to note the resulting root-development in these cases also. 
* W. Detmer, ‘ Practical Plant Physiology,’ trans. by S. A. Moor (1898), Third Section, 
pp. 951-3. 
