NEW CELL FORIVLVTIONS IN PLANTS 287 



in the rapidity of elongation of the internodes depends on so many 

 factors, such as weather, soil moisture, age and position on the shoot, 

 that it was not possible to arrange series that did not show a great amount 

 of variation. This indicates that great care should be exercised in 

 the interpretation of the data. All facts considered, however, the general 

 conclusions that have been reached are as follows: 



(1) The length of the injected internode normally would be inter- 

 mediate between that of the one above and the one below, but the differ- 

 ences between them would be slight. This does not hold if the parts 

 measured were too near the ground, for the internodes near the ground are 

 much shorter than those a little higher up. 



(2) After the injection there followed a short period of normal length- 

 ening, subsequent to which the injected internode slackened growth. 



(3) The internodes above and below the injected one continued 

 to lengthen normally or nearly so. A point must here be noted that 

 cannot be determined until the plant has been cut down and dissected. 

 Sometimes, either thru the action of the injected substance or because 

 of a deficiency in the internodal septum, the fluid finds its way into 

 the internode below that injected, affecting that as well as the one 

 originally treated. 



(4) The stunting of the injected internode was permanent. No 

 reassumption of activity tending to increase of length appeared. The 

 diameter increase is about as normal. 



On examination of the graphs one notices that the internode above 

 the one injected lengthens rapidly, until it is of the long^t of the three 

 considered. That this is due to the effect of the injection is doubtful. 

 The position on the stem was probably the most potent factor in causing 

 this increase. The injected plants were not rendered sickly by the treat- 

 ment; they were quite as healthy as the controls. This is only true 

 of those where the tissue destruction was not great. One measurement 

 was made of the plants about two weeks after the close of the regular 

 measurements, and it showed an increase in length of the upper internode 

 only, and that of but two to five millimeters. The point of importance 

 in the graphs is the dwarfing of the injected internode. That there was 

 some slight effect on the growth of the adjacent internodes was very prob- 

 able, but the data are insufficent to demonstrate it. 



Besides the cases used to illustrate these points, a number of addition- 

 al observations were made, all on Polygonum. 



